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Journal articles on the topic 'Optická vlna'

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Published: 4 June 2021
Last updated: 10 February 2022

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1

Msongaleli, Dawson, Kerem Kucuk, and Adnan Kavak. "Adaptive Polling Medium Access Control Protocol for Optic Wireless Networks." Applied Sciences 9, no. 6 (2019): 1071. http://dx.doi.org/10.3390/app9061071.

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The emergence of optical wireless networks (OWNs) is a potential solution to the quest for the increasing bandwidth demand. Existing bandwidth assignment strategies are not suitable for OWNs, considering factors such as differences between the physical properties of radio networks and OWNs. In order to eliminate collision, minimize delay and enhance system utilization and fairness, we propose the non-contention bandwidth assignment protocol called adaptive polling medium access control (APMAC) protocol for OWNs. The APMAC protocol involves association, data transmission and dissociation phases
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2

Wrobel, J. M., R. C. Walker, and A. H. Bridle. "The relativistic Jet in M84." Symposium - International Astronomical Union 175 (1996): 131–32. http://dx.doi.org/10.1017/s0074180900080311.

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The elliptical galaxy M84 (NGC 4374, UGC 07494) hosts an FR-I radio continuum source (Laing & Bridle 1987, MNRAS, 228, 557) and a dusty, warped optical emission line “disk” (Baumet al.1988, ApJS, 68, 643; Goudfrooijet al.1994, A&ApS, 105, 341). HST imaging shows that the inner dust distribution is not relaxed, but filamentary and complex (Jaffeet al.1994, AJ, 108, 1567). M84 is a member of the Virgo Cluster, at which distance 1 arcsec = 73 pc independent of Hubble's constant (Jacobyet al.1990, ApJ, 356, 332). Our VLA imaging, at 6 cm with a resolution of 500 mas (36 pc) FWHM, shows tha
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3

Beasley, A. J., V. Dhawan, E. B. Fomalont, R. C. Walker, and J. M. Wrobel. "The VLBA Calibrator Survey." Symposium - International Astronomical Union 175 (1996): 527–28. http://dx.doi.org/10.1017/s0074180900081730.

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Using phase-referencing, the coherent integration time of VLBI observations can be substantially increased, permitting observations of weaker (≃mJy) target sources (see e.g. Beasley & Conway 1995). The position of a source can also be accurately measured relative to a reference source, allowing absolute and proper-motion measurements, optical-radio image alignment, and alignment of images made at different frequencies.
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4

Kovalevsky, J. "Optical-Radio Reference Ties." International Astronomical Union Colloquium 165 (1997): 447–48. http://dx.doi.org/10.1017/s0252921100046935.

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In the course of the Hipparcos data reduction, the system of coordinates obtained is the result of complicated and partly random processes. It is therefore an arbitrary system which could not be retained. It was decided to compute a rotation ϵ at epoch (1991.25) and a time-dependent rotation ω (or spin) such that, when applied, it would be a realisation of the IAU extragalactic reference system as defined in 1991 and implemented by IERS in 1995.A working group was set up by the Hipparcos Science Team with the task to provide these rotations from all possible techniques. Actually eleven indepen
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Yang, Jun, Zsolt Paragi, Robert J. Beswick, et al. "A compact core-jet structure in the changing-look Seyfert NGC 2617." Monthly Notices of the Royal Astronomical Society 503, no. 3 (2021): 3886–95. http://dx.doi.org/10.1093/mnras/stab706.

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ABSTRACT The nearby face-on spiral galaxy NGC 2617 underwent an unambiguous ‘inside–out’ multiwavelength outburst in Spring 2013, and a dramatic Seyfert-type change probably between 2010 and 2012, with the emergence of broad optical emission lines. To search for the jet activity associated with this variable accretion activity, we carried out multiresolution and multiwavelength radio observations. Using the very long baseline interferometric (VLBI) observations with the European VLBI Network at 1.7 and 5.0 GHz, we find that NGC 2617 shows a partially synchrotron self-absorbed compact radio cor
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6

Denn, G., and R. Mutel. "VLBA Studies of BL Lac." Symposium - International Astronomical Union 175 (1996): 41–42. http://dx.doi.org/10.1017/s0074180900079936.

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The radio core of BL Lac has been monitored with VLBI techniques since 1980. At least seven superluminal events have been seen, usually associated with flux outbursts. The components have been interpreted as weak relativistic shocks associated with opposed jets. Recent dramatic changes in the nucleus of BL Lac have been seen: optical spectra (Lawrence et al. 1995) show the presence of broad-line Hα and [NII] emission lines. The single-dish radio flux has also increased by 3 times in the past year. Often in BL Lac's past, a flux outburst immediately precedes the ejection of a new superluminal c
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7

Walter, H. G., R. Hering, H. Lenhardt, Chr deVegt, D. R. Florkowski, and K. J. Johnston. "Accuracy Assessment of Hipparcos Optical and VLA Radio Positions of Stars." Symposium - International Astronomical Union 156 (1993): 377–80. http://dx.doi.org/10.1017/s007418090017353x.

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Optical positions of some 30 radio stars derived from 12 months of HIPPARCOS measurements are compared with their radio positions obtained with the Very Large Array (VLA). — Once the lengths of arcs between optical and radio positions of pairs of stars are calculated the differences of the arcs are formed. They provide an estimate of the coincidence of the optical and radio emission centres. — From the comparison of optical and radio positions infinitesimal rotation angles of the HIPPARCOS frame with respect to the VLA extragalactic reference frame are determined by rigid rotations. After taki
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8

Troitskiy, I. S., D. A. Morozova, S. G. Jorstad, et al. "Multiwavelength Observations of 6 FSRQ in 2008–2012." Proceedings of the International Astronomical Union 9, S304 (2013): 249–51. http://dx.doi.org/10.1017/s1743921314003974.

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AbstractWe present results of 4 years of VLBA monitoring along with γ-ray and optical R-band photometric observations of 6 blazars (0420-014, 1156+295, 1222+216, PKS 1510-089, 1633+382 and CTA 102). We have analyzed total intensity images obtained with the VLBA at 43 GHz and investigated kinematic evolution of the pc-scale jets of the sources. For all sources we compare flux variations in the VLBI core and bright superluminal knots with γ-ray and optical light curves. The majority of γ-ray flares are coincident with the appearance of a new superluminal knot and/or a flare in the millimeter-wav
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9

Vigotti, M., S. G. Djorgovski, L. Gregorini, et al. "The B3-VLA Sample." Symposium - International Astronomical Union 175 (1996): 519–21. http://dx.doi.org/10.1017/s0074180900081705.

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The use of radio sources to identify the most distant object in the Universe has been proved to be a very successful approach in observational cosmology. Studies of high flux, powerful 3CR and 1-Jy galaxies show dramatic evidence for color and luminosity evolution, reaching to look-back times 80% of the Hubble time. In order to disentangle the selection effect, correlation with redshift, and correlation with radio power, it is necessary to obtain well defined, complete samples of radio galaxies at a large range of redshifts, and with a wide baseline of radio power. We need the identifications
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10

Whiteoak, J. B., and F. F. Gardner. "VLA Observations of NGC 5793." Publications of the Astronomical Society of Australia 7, no. 1 (1987): 88–91. http://dx.doi.org/10.1017/s1323358000021913.

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AbstractThe edge-on spiral galaxy NGC 5793 has been observed at frequencies of 4860 and 14940 MHz with the Very Large Array. The corresponding half-intensity beamwidths in the final maps were 0.65 × 0.40 and 0.19 × 0.11 arcsec2. The maps show a continuum source close to the optical nucleus with dimensions of ≤0.01 and 0.04 arcsec in right ascension and declination. The average spectral index is –0.6.
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Verdoes Kleijn, G. A., P. T. de Zeeuw, S. A. Baum, et al. "The Nuclei of Nearby Radio-Loud Ellipticals." Symposium - International Astronomical Union 205 (2001): 62–65. http://dx.doi.org/10.1017/s0074180900220433.

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We have observed a complete sample of 21 nearby (D < 70h−1Mpc) Fanaroff & Riley Type I galaxies with HST/WFPC2 and detected dust disks and lanes in 19 of them. The radio jets are roughly perpendicular to the dust which is used to constrain the Doppler boosting factors of the radio jet and cores. The VLBA core flux correlates with the central Hα+[NII] flux which might indicate that the VLBA core is dominated by an isotropic component. Twelve galaxies show nuclear optical sources. We discuss various possible origins for this emission.
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12

Harrison, Ian, Michael L. Brown, Ben Tunbridge, et al. "SuperCLASS – III. Weak lensing from radio and optical observations in Data Release 1." Monthly Notices of the Royal Astronomical Society 495, no. 2 (2020): 1737–59. http://dx.doi.org/10.1093/mnras/staa696.

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ABSTRACT We describe the first results on weak gravitational lensing from the SuperCLASS survey: the first survey specifically designed to measure the weak lensing effect in radio-wavelength data, both alone and in cross-correlation with optical data. We analyse $1.53 \, \mathrm{deg}^2$ of optical data from the Subaru telescope and $0.26 \, \mathrm{deg}^2$ of radio data from the e-MERLIN and VLA telescopes (the DR1 data set). Using standard methodologies on the optical data only we make a significant (10σ) detection of the weak lensing signal (a shear power spectrum) due to the massive supercl
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13

Byrne, P. B., and D. E. Gary. "A Flare on AD Leo observed in Optical, UV and Microwaves." International Astronomical Union Colloquium 104, no. 2 (1989): 63–66. http://dx.doi.org/10.1017/s0252921100153813.

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SummaryWe report a simultaneous IUE, VLA and ground-based photometric observation of a flare on the dMe star, AD Leo, on 2nd February 1903. The optical flare was extremely impulsive, lasting in total only about 3 mins. A relatively longlived 6 cm flare was observed with the VLA which was initially 100% polarized. An IUE spectrum, taken ≈ 8 min after the onset of the optical U band flare, shows motu than a factor of 2 increase in the Ha II λ 1640Å emission line. The other mid-transition region lines such as C IV λλ154B/52Å show almost no response.
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14

Kollatschny, W., P. M. Weilbacher, M. W. Ochmann, et al. "NGC 6240: A triple nucleus system in the advanced or final state of merging." Astronomy & Astrophysics 633 (January 2020): A79. http://dx.doi.org/10.1051/0004-6361/201936540.

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Aims. NGC 6240 is a well-studied nearby galaxy system in the process of merging. Based on optical, X-ray, and radio observations, it is thought to harbor two active nuclei. We carried out a detailed optical 3D spectroscopic study to investigate the inner region of this system in connection with existing MERLIN and VLBA data. Methods. We observed NGC 6240 with very high spatial resolution using the MUSE instrument in the Narrow-Field Mode with the four-laser GALACSI adaptive optics system on the ESO VLT under seeing conditions of 0″.49. Our 3D spectra cover the wavelength range from 4725 to 935
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15

Stanway, E. R., T. R. Marsh, P. Chote, B. T. Gänsicke, D. Steeghs, and P. J. Wheatley. "VLA radio observations of AR Scorpii." Astronomy & Astrophysics 611 (March 2018): A66. http://dx.doi.org/10.1051/0004-6361/201732380.

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Aims. AR Scorpii is unique amongst known white dwarf binaries in showing powerful pulsations extending to radio frequencies. Here we aim to investigate the multi-frequency radio emission of AR Sco in detail, in order to constrain its origin and emission mechanisms. Methods. We present interferometric radio frequency imaging of AR Sco at 1.5, 5 and 9 GHz, analysing the total flux and polarization behaviour of this source at high time resolution (10, 3 and 3 s), across a full 3.6 h orbital period in each band. Results. We find strong modulation of the radio flux on the orbital period and the orb
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16

Rubinur, K., P. Kharb, M. Das, et al. "A multiwavelength study of the dual nuclei in Mrk 212." Monthly Notices of the Royal Astronomical Society 500, no. 3 (2020): 3908–19. http://dx.doi.org/10.1093/mnras/staa3375.

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ABSTRACT We present radio observations of the galaxy merger remnant Mrk 212 with the Karl G. Jansky Very Large Array (VLA) and the upgraded Giant Meter Radio Telescope (uGMRT). Mrk 212 has two previously known radio sources associated with the two optical nuclei, S1 and S2, with a projected separation of ∼6 kpc, making it a dual active galactic nuclei (AGN) candidate. Our new 15-GHz VLA observations reveal that S1 is a double radio source centred around the optical nucleus; its total extent is ∼750 pc its average 1.4−8.5 GHz spectral index is −0.81 ± 0.06. S1 therefore resembles a compact symm
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17

Kaplan, G. H., K. J. Johnston, P. K. Seidelmann, C. M. Wade, and T. S. Carroll. "Fundamental radio reference frame from VLA observations of minor planets." Symposium - International Astronomical Union 128 (1988): 97. http://dx.doi.org/10.1017/s0074180900119333.

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The weak thermal emission from the largest minor planets can be detected in the microwave regime by the Very Large Array (VLA). Signal-to-noise ratios are sufficiently high to permit precise measurement of the positions of these objects at all points in their orbits with respect to background extragalactic sources. We are in the process of obtaining observations of astrometric accuracy for minor planets 1 Ceres, 2 Pallas, 4 Vesta, and 10 Hygeia.Minor planets have historically served as “test particles” in the solar system, and optical observations of these objects have been valuable in the det
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18

Johnston, K. J., and Chr de Vegt. "Comparison of the Optical and Radio Reference Frames." Highlights of Astronomy 7 (1986): 103–8. http://dx.doi.org/10.1017/s1539299600006304.

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The Very Large Array (VLA) has made possible the measurement of the precise positions of the radio emission associated with stars. This allows the direct comparison of the optical reference frame (FK4) with the radio reference frame which is defined by the quasi-absolute positions of extragalactic radio sources. This comparison is limited by the small number of bright stars that display detectable radio emission and the lack of knowledge of the precise coincidence of the radio emission with the optical photocenter of the star. Since the VLA is the most sensitive astrometrically capable radio t
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19

Caillault, Jean-Pierre, and Stephen Drake. "Full Phase Coverage of BY Dra with the VLA." International Astronomical Union Colloquium 130 (1991): 494–97. http://dx.doi.org/10.1017/s0252921100080246.

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AbstractWe have obtained 21 ~one-hour observations of the prototypical spotted star, BY Dra, with the VLA. These data are sufficiently well spaced in time to allow for complete rotational and orbital phase coverage; the resultant radio light curves are compared to their optical counterpart. We also plot the emission versus time without phase-folding, in order to search for longer periods of activity. Splitting the data into smaller (three minute) time bins allows for the determination of the normalized amplitude distribution of the flux; we compare this with known stellar optical and X-ray fla
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20

Zanichelli, A., L. Gregorini, and M. Bondi. "Radio-optical properties of extragalactic populations in the VIPERS Survey." Proceedings of the International Astronomical Union 10, S309 (2014): 317. http://dx.doi.org/10.1017/s1743921314010138.

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21

Miller-Jones, James C. A., Gregory R. Sivakoff, Diego Altamirano, et al. "Investigating accretion disk – radio jet coupling across the stellar mass scale." Proceedings of the International Astronomical Union 6, S275 (2010): 224–32. http://dx.doi.org/10.1017/s1743921310016078.

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AbstractRelationships between the X-ray and radio behavior of black hole X-ray binaries during outbursts have established a fundamental coupling between the accretion disks and radio jets in these systems. I begin by reviewing the prevailing paradigm for this disk-jet coupling, also highlighting what we know about similarities and differences with neutron star and white dwarf binaries. Until recently, this paradigm had not been directly tested with dedicated high-angular resolution radio imaging over entire outbursts. Moreover, such high-resolution monitoring campaigns had not previously targe
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22

Beall, James H. "FROM GALACTIC TO EXTRAGALACTIC JETS: A REVIEW." Acta Polytechnica 53, A (2013): 671–76. http://dx.doi.org/10.14311/ap.2013.53.0671.

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An analysis of the data that have recently become available from observing campaigns, including VLA, VLBA, and satellite instruments, shows some remarkable similarities and significant differences in the data from some epochs of galactic microquasars, including GRS 1915+105, the concurrent radio and X-ray data [3] on Centaurus A (NGC 5128), 3C120 [35], and 3C454.3 as reported by Bonning et al. [16], which showed the first results from the Fermi Space Telescope for the concurrent variability at optical, UV, IR, and g-ray variability of that source. In combination with observations from microqua
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Gabányi, K. É., S. Frey та T. An. "Is 4C+29.48 a γ-ray source?" Astronomy & Astrophysics 612 (квітень 2018): A109. http://dx.doi.org/10.1051/0004-6361/201732286.

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Context. The Fermi Large Area Telescope revealed that the extragalactic γ-ray sky is dominated by blazars, active galactic nuclei (AGN) whose jet is seen at very small angle to the line of sight. To associate and then classify the γ-ray sources, data have been collected from lower frequency surveys and observations. Since those have superior angular resolution and positional accuracy compared to the γ-ray observations, some associations are not straightforward. Aims. The γ-ray source 3FGL J1323.0+2942 is associated with the radio source 4C+29.48 and classified as a blazar of unknown type, lack
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Becker, R. H., M. D. Gregg, D. J. Helfand, C. M. Cress, R. Mcmahon, and R. L. White. "First Results from the VLA FIRST Survey." Symposium - International Astronomical Union 175 (1996): 499–502. http://dx.doi.org/10.1017/s007418090008164x.

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The VLA FIRST survey is now in its second year. We have completed mapping over 1500 deg2 of the North Galactic Cap and present here the catalog of the 138,000 radio sources detected therein. We discuss the statistics of this new catalog including the two-point angular correlation function for all radio emitters, present our optical identification of 24,000 sources using the APM catalog, and report followup studies on radio variability, X-ray source identification, and our bright quasar sample.
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Butuzova, Marina S., and Alexander B. Pushkarev. "Is OJ 287 a Single Supermassive Black Hole?" Universe 6, no. 11 (2020): 191. http://dx.doi.org/10.3390/universe6110191.

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Light curves for more than century optical photometric observations of the blazar OJ 287 reveals strong flares with a quasi-period of about 12 years. For a long time, this period has been interpreted by processes in a binary black hole system. We propose an alternative explanation for this period, which is based on Doppler factor periodic variations of the emitting region caused by jet helicity. Using multi-epoch very large baseline interferometry (VLBI) observations carried out in a framework of the MOJAVE (Monitoring Of Jets in Active galactic nuclei with VLBA Experiments) program and other
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Congiu, E., P. Kharb, A. Tarchi, et al. "The radio structure of the narrow-line Seyfert 1 Mrk 783 with VLBA and e-MERLIN." Monthly Notices of the Royal Astronomical Society 499, no. 3 (2020): 3149–57. http://dx.doi.org/10.1093/mnras/staa3024.

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ABSTRACT In this paper, we present the analysis of new radio and optical observations of the narrow-line Seyfert 1 galaxy Mrk 783. $1.6\, \mathrm{GHz}$ observations performed with the e-MERLIN interferometer confirm the presence of the diffuse emission previously observed. The Very Long Baseline Array (VLBA) also detects the nuclear source both at $1.6\, \mathrm{GHz}$ (L band) and $5\, \mathrm{GHz}$ (C band). While the L-band image shows only an unresolved core, the C-band image shows the presence of a partially resolved structure at a position angle of 60○. The brightness temperature of the e
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Chen, Yu-Ching, Xin Liu, Wei-Ting Liao, and Hengxiao Guo. "Very Large Array imaging rules out precessing radio jets in three DES–SDSS-selected candidate periodic quasars." Monthly Notices of the Royal Astronomical Society 507, no. 3 (2021): 4638–45. http://dx.doi.org/10.1093/mnras/stab2397.

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ABSTRACT Periodic quasars have been suggested as candidates for hosting binary supermassive black holes (SMBHs), although alternative scenarios remain possible to explain the optical light-curve periodicity. To test the alternative hypothesis of precessing radio jet, we present deep 6 GHz radio imaging conducted with NSF’s Karl G. Jansky Very Large Array (VLA) in its C configuration for the three candidate periodic quasars, DES J024703.24−010032.0, DES J024944.66−000036.8, and DES J025214.67−002813.7. Our targets were selected based on their optical variability using 20 yr long multicolour lig
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28

Haarsma, Deborah B., Joshua N. Winn, Emilio E. Falco, et al. "The FIRST-Optical-VLA Survey for Lensed Radio Lobes." Astronomical Journal 130, no. 5 (2005): 1977–95. http://dx.doi.org/10.1086/466513.

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Fomalont, E. B. "The Radio Sky at Micro-Jy Levels." Symposium - International Astronomical Union 175 (1996): 555–58. http://dx.doi.org/10.1017/s0074180900081833.

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The properties of the μJy radio sources are described in this paper. The results were obtained from deep VLA observations of four fields, shown in Table 1. Deep optical images have been obtained for the Bootes and Lilly 1 fields.
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Wilcots, Eric M., Cathy Lehman, and Bryan Miller. "HI Observations of Barred Magellanic Type Galaxies." International Astronomical Union Colloquium 157 (1996): 126–28. http://dx.doi.org/10.1017/s0252921100049617.

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We present the results of a VLA D-configuration survey of a sample of Barred Magellanic type (SBm/IBm) galaxies. The data show that: (1) the HI is extended well beyond the optical diameter; (2) the HI distribution often has a different position angle than the optical distribution; (3) the bar morphology is typically manifested in the HI kinematics; (4) these galaxies not only tend to have gaseous companions, but they also tend to be strongly interacting systems; and (5) the companions have no obvious optical counterparts.
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Sepúlveda, Inma, Robert Estalella, Guillem Anglada, et al. "VLA ammonia observations of L1287." Astronomy & Astrophysics 644 (December 2020): A128. http://dx.doi.org/10.1051/0004-6361/202037895.

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Aims. In this paper, we study the dense gas of the molecular cloud LDN 1287 (L1287), which harbors a double FU Ori system, an energetic molecular outflow, and a still-forming cluster of deeply embedded low-mass young stellar objects that show a high level of fragmentation. Methods. We present optical Hα and [SII], and VLA NH3 (1, 1) and (2, 2) observations with an angular resolution of ~3′′.5. The observed NH3 spectra have been analyzed with the Hyperfine Structure tool, fitting simultaneously three different velocity components. Results. The NH3 emission from L1287 comes from four different s
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32

Terzian, Yervant. "Expansion distances of Planetary Nebulae." Symposium - International Astronomical Union 180 (1997): 29–39. http://dx.doi.org/10.1017/s0074180900129754.

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The distances of planetary nebulae are discussed as derived from their angular expansions and radial expansion velocities. An assessment is given of distances derived by this method both at optical and radio wavelengths. The recent VLA radio data show promise in establishing a more accurate distance scale for planetary nebulae.
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Williams, B. A., J. H. Van Gorkom, Min Yun, and Lourdes Verdes-Montenegro. "VLA Observations of Neutral Hydrogen in Compact Groups." Symposium - International Astronomical Union 186 (1999): 375–82. http://dx.doi.org/10.1017/s0074180900113142.

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VLA images of the neutral hydrogen (HI) in the direction of HCG 2, 16, 33, 88, and 92 (Stephan's Quintet) are examined. In HCG 2 and 16, the HI gas is bound to the individual galaxies but shows definite signs of tidal interaction; while in HCG 92, the more compact configuration, the HI gas is contained within a few prominent cloud features well displaced from the optical positions of any of the spiral members. In every case, the motions of the gas are consistent with the motions of the galaxies within the Hickson groups. A range of kinematical properties is observed for the HI gas, from well-o
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Churchwell, E., and W. M. Goss. "A High‐Resolution VLA and Optical Study of NGC 604." Astrophysical Journal 514, no. 1 (1999): 188–94. http://dx.doi.org/10.1086/306941.

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Hillier, Tom, Michael L. Brown, Ian Harrison, and Lee Whittaker. "Radio–optical galaxy shape and shear correlations in the COSMOS field using 3 GHz VLA observations." Monthly Notices of the Royal Astronomical Society 488, no. 4 (2019): 5420–36. http://dx.doi.org/10.1093/mnras/stz2098.

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Abstract We present a weak-lensing analysis of the 3 GHz Very Large Array radio survey of the COSMOS field, which we correlate with overlapping Hubble Space Telescope-Advanced Camera for Survey optical observations using both intrinsic galaxy shape and cosmic shear correlation statistics. After cross-matching sources between the two catalogues, we measure the correlations of galaxy position angles and find a Pearson correlation coefficient of 0.14 ± 0.03. This is a marked improvement from previous studies which found very weak, or non-existent correlations, and gives insight into the emission
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Hagiwara, Y., R. Kawabe, N. Nakai, and P. J. Diamond. "The Nuclear Region of a Megamaser in a Southern AGN, NGC 5793: Parsec-Scale Structure and OH Absorption." International Astronomical Union Colloquium 164 (1998): 233–34. http://dx.doi.org/10.1017/s0252921100045358.

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AbstractWe have carried out VLBA observations of the OH absorption lines toward the nucleus of the active galaxy, NGC 5793, which is known to have a megamaser in its center. We have also successfully made its continuum image at the L band. It reveals the typical “core-jet” structure on parsec scales. Uniform values of optical depth at each point against the background radio continuum source shows that the column densities of the OH absorbing cloud uniformly distributes around the radio compact nucleus.
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Lee, Ting-Hui, Sun Kwok, and Jeremy Lim. "Extinction Maps and Dust Distribution of Planetary Nebulae." Symposium - International Astronomical Union 209 (2003): 317–18. http://dx.doi.org/10.1017/s0074180900208917.

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We present an indirect method to probe the dust distribution in PNe. Using the free-free continuum flux density and Hβ recombination line flux relationship and the Case B Hα/Hβ line ratio, we determined the expected Hα flux from the radio continuum maps. The dust optical depth distribution of each planetary nebula was then derived from the expected to observed Hα flux ratio. With HST WFPC2 and VLA A-array observations, dust optical depth maps with resolution as high as ~ 0.1″ can be obtained.
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38

de Vegt, Chr, N. Zacharias, K. J. Johnston, and R. Hindsley. "Improving the Reference Frame by Radio–and Optical Astrometry of Radio Stars." International Astronomical Union Colloquium 127 (1991): 246–49. http://dx.doi.org/10.1017/s0252921100063880.

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AbstractA longterm program of precise radio – and optical astrometry of selected radio stars has been conducted in the last decade by our observatories using the VLA and astrographs on both hemispheres. Positions of 54 stars north of −26 deg. declination including 6 MASER stars have been obtained. The program status and some results from the southern hemisphere are reported.
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39

Simkin, S. M., and J. Callcut. "A Search for HI in Strong Radio Galaxies." Symposium - International Astronomical Union 175 (1996): 183–84. http://dx.doi.org/10.1017/s0074180900080475.

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In the past decade it has become clear that many classical, double radio galaxies have hosts with extensive ionized gas inside the body of the optical galaxy (Hansen et al., 1987) (Baum et al., 1988). We have observed three such sources (PKS349-27, PKS634-20, and Pictor A) in both Hα and HI (with the VLA).
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40

Leslie, Sarah, Lisa Kewley, Elaine Sadler, and Julia Bryant. "A Radio-Optical Study of Resolved Star Formation in SAMI Galaxies." Proceedings of the International Astronomical Union 10, S309 (2014): 324. http://dx.doi.org/10.1017/s1743921314010199.

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AbstractWith integral field spectroscopic data from the the Sydney-AAO Multi-object Integral-field spectrograph (SAMI) survey and the VLA, we will study the relationship between star formation (as traced by Hα emission) and the radio continuum emission within galaxies with the aim of better understanding the intricacies of local scaling relations.
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41

Wang, Y., H. Beuther, M. R. Rugel, et al. "The HI/OH/Recombination line survey of the inner Milky Way (THOR): data release 2 and H I overview." Astronomy & Astrophysics 634 (February 2020): A83. http://dx.doi.org/10.1051/0004-6361/201937095.

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Context. The Galactic plane has been observed extensively by a large number of Galactic plane surveys from infrared to radio wavelengths at an angular resolution below 40′′. However, a 21 cm line and continuum survey with comparable spatial resolution is lacking. Aims. The first half of THOR data (l = 14.0°−37.9°, and l = 47.1°−51.2°, |b|≤ 1.25°) has been published in our data release 1 paper. With this data release 2 paper, we publish all the remaining spectral line data and Stokes I continuum data with high angular resolution (10′′–40′′), including a new H I dataset for the whole THOR survey
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42

Hutchings, J. B., A. C. Gower, S. Ryneveld, and A. Dewey. "Quasar Radio Structure in Cluster Environments." Symposium - International Astronomical Union 175 (1996): 329–30. http://dx.doi.org/10.1017/s0074180900080980.

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We have VLA snapshots at 6cm and 20cm of ≃50 QSOs of redshift ≤0.7 with a range of known optical galaxy environments. The radio sources were characterised by measures of flux, size, and shape. The cluster density of the QSOs is given by the Bgq number from galaxy companion data largely published by Yee and Ellingson (e.g. ApJ 411, 43, 1993).
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43

Wrobel, J. M., G. B. Taylor, T. A. Rector, S. T. Myers, and C. D. Fassnacht. "Faint Radio Sources in the NOAO Boötes Field: VLBA Imaging and Optical Identifications." Astronomical Journal 130, no. 3 (2005): 923–35. http://dx.doi.org/10.1086/432605.

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44

Montmerle, T., P. André, E. D. Feigelson, P. Stine та J. Bouvier. "Repeated Multiple-Frequency VLA Surveys of the ρ Ophiuchi Cloud". Symposium - International Astronomical Union 115 (1987): 45–47. http://dx.doi.org/10.1017/s0074180900094791.

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Our goal was to look for radio non-thermal emission from active PMS stars, as suggested by the presence of numerous, highly variable X-rays sources in the cloud (Montmerle et al. 1983), and by optical periodicities probably linked with starspots (Bouvier and Bertout, in prep.). Previous radio surveys have been done by Brown and Zuckermann (1975), and Falgarone and Gilmore (1981). Emission mechanisms are mainly thermal (free-free, from H II regions, winds, accretion flows; gyrosynchrotron), and non-thermal (gyrosynchrotron from flares; synchrotron in winds, White 1985; corotating interaction re
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45

Whitmore, Bradley C., Crystal Brogan, Rupali Chandar, et al. "A multi-wavelength classification system for the evolution of star clusters." Proceedings of the International Astronomical Union 11, S315 (2015): 142–45. http://dx.doi.org/10.1017/s1743921316007419.

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AbstractThe availability of high spatial resolution molecular gas observations from ALMA, and similar resolution observations in the radio continuum using the VLA, is providing the opportunity to make comparisons with specific features seen in optical observations more directly than in the past. Using our ALMA observations of the Antennae galaxies as a springboard, we have compared the locations of small-scale CO (3−2) features with a variety of multi-wavelength observations, in particular optical and near-infrared imaging using both broad (UBVI) and narrow-band data (Hαand Paβ) taken with the
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46

Morrison, LV, RW Argyle, Y. Requième, and JM Mazurier. "Comparison of Optical and Radio Positions of Stars." Symposium - International Astronomical Union 141 (1990): 513–14. http://dx.doi.org/10.1017/s0074180900087477.

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The positions of radio stars measured with respect to the VLBI network of extragalactic sources provides an important link between the optical and extragalactic reference frames. The establishment of this link was brought a stage nearer realization with the publication by Florkowski et al.(1985) of the radio positions of 20 stars measured with the Very Large Array (VLA) of the National Radio Astronomy Observatory, and the publication by Lestrade et al.(1985, 1988) of 10 stars measured with the VLBI network.
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47

Slee, OB, AL Roy, and H. Andernach. "A VLA Survey of Rich Clusters of Galaxies III. The Weaker Sources: Maps and Identifications." Australian Journal of Physics 49, no. 5 (1996): 977. http://dx.doi.org/10.1071/ph960977.

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We present radio and optical parameters for 737 weak sources in 60 Abell cluster fields observed with the Very Large Array (VLA) using scaled arrays at 1.5 and 4.9 GHz. The measurements extend to a lower 1.5 GHz limit of 1.0 mJy and comprise a complete sample with 1.5 GHz flux density 2.5 ≤ S1.5 −3 sr, and the cluster fields are distributed over 24 h of right ascension and between declinations +35° and −30°. Contour maps of the extended sources at 1.5 GHz are presented and source parameters such as position, angular size and spectral index are tabulated. We also derive the emitted power and li
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48

Rubin, Vera C., Alan P. Boss, W. Kent, Jr Ford, and Jeffrey D. Kenney. "A comparison of optical and VLA rotation curves for Virgo spirals." Astronomical Journal 98 (October 1989): 1246. http://dx.doi.org/10.1086/115211.

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49

Van Dyk, Schuyler D., K. W. Weiler, R. A. Sramek, et al. "Supernovae at the Highest Angular Resolution." Symposium - International Astronomical Union 205 (2001): 390–91. http://dx.doi.org/10.1017/s0074180900221554.

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The study of supernovae (SNe) and their environments in host galaxies at the highest possible angular resolution in a number of wavelength regimes is providing vital clues to the nature of their progenitor stars. We are observing SNe in the radio using the Very Large Array (VLA) and VLBI, in the X-rays with Chandra, and in the optical at the subarcsecond resolution of HST.
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50

Burke, Bernard F. "Gravitational Lenses: Observations." Symposium - International Astronomical Union 119 (1986): 517–27. http://dx.doi.org/10.1017/s0074180900153367.

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The gravitational lens phenomenon is shown to be not uncommon. A search is now underway to find a larger number of examples, using the VLA to search for candidates, following up with optical observations to establish equality of redshifts in the images. Most of the present lensing examples exhibit anomalous behavior that is most easily understood as evidence for large quantities of intervening non-luminous matter.
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