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Start Over Subject radio astronomy Publisher CDS
1691. The HII Region Discovery Survey (HRDS). II.
ID:
ivo://CDS.VizieR/J/ApJS/194/32
Title:
The HII Region Discovery Survey (HRDS). II.
Short Name:
J/ApJS/194/32
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Green Bank Telescope (GBT) HII Region Discovery Survey has doubled the number of known HII regions in the Galactic zone 343{deg}<=l<=67{deg} with |b|<=1{deg}. We detected 603 discrete hydrogen radio recombination line (RRL) components at 9GHz (3cm) from 448 targets. Our targets were selected based on spatially coincident mid-infrared and 20cm radio continuum emission. Such sources are almost invariably HII regions; we detected hydrogen RRL emission from 95% of our target sample. The sensitivity of the GBT and the power of its spectrometer together made this survey possible. Here, we provide a catalog of the measured properties of the RRL and continuum emission from the survey nebulae. The derived survey completeness limit, 180mJy at 9GHz, is sufficient to detect all HII regions ionized by single O-stars to a distance of 12kpc. We discovered 34 first quadrant negative-velocity HII regions, which lie at extreme distances from the Sun and appear to be part of the Outer Arm. We found RRL emission from 208 Spitzer GLIMPSE 8.0um "bubble" sources, 65 of which have been cataloged previously. It thus appears that nearly all GLIMPSE bubbles are HII regions and that ~50% of all Galactic HII regions have a bubble morphology at 8.0um.
1692. The invisible AGN catalogue
ID:
ivo://CDS.VizieR/J/MNRAS/468/196
Title:
The invisible AGN catalogue
Short Name:
J/MNRAS/468/196
Date:
21 Oct 2021
Publisher:
CDS
Description:
A large fraction of active galactic nuclei (AGN) are 'invisible' in extant optical surveys due to either distance or dust-obscuration. The existence of this large population of dust-obscured, infrared (IR)-bright AGN is predicted by models of galaxy-supermassive black hole coevolution and is required to explain the observed X-ray and IR backgrounds. Recently, IR colour cuts with Wide-field Infrared Survey Explorer have identified a portion of this missing population. However, as the host galaxy brightness relative to that of the AGN increases, it becomes increasingly difficult to differentiate between IR emission originating from the AGN and from its host galaxy. As a solution, we have developed a new method to select obscured AGN using their 20-cm continuum emission to identify the objects as AGN. We created the resulting invisible AGN catalogue by selecting objects that are detected in AllWISE (mid-IR) and FIRST (20 cm), but are not detected in SDSS (optical) or 2MASS (near-IR), producing a final catalogue of 46 258 objects. 30 per cent of the objects are selected by existing selection methods, while the remaining 70 per cent represent a potential previously unidentified population of candidate AGN that are missed by mid-IR colour cuts. Additionally, by relying on a radio continuum detection, this technique is efficient at detecting radio-loud AGN at z>=0.29, regardless of their level of dust obscuration or their host galaxy's relative brightness.
1693. The {lambda}-Orionis ring in CO
ID:
ivo://CDS.VizieR/J/A+A/357/1001
Title:
The {lambda}-Orionis ring in CO
Short Name:
J/A+A/357/1001
Date:
21 Oct 2021
Publisher:
CDS
Description:
The table shows clump parameters for 130 peaks in CO(J=1->0) emission detected in the Lambda-Orionis ring in the survey of Lang et al. (1998PASA...15...70L). The clumps were isolated using the Clumpfind algorithm of Williams et al. (1994, Cat. <J/ApJ/428/693>). They are ordered and labelled according to the relative brightness of the peak temperatures within them, so clump 1 contains the emission maximum, but not necessarily the maximum W(CO) or largest mass.
1694. The Megamaser Cosmology Project (MCP). III.
ID:
ivo://CDS.VizieR/J/ApJ/727/20
Title:
The Megamaser Cosmology Project (MCP). III.
Short Name:
J/ApJ/727/20
Date:
21 Oct 2021
Publisher:
CDS
Description:
Observations of H_2_O masers from circumnuclear disks in active galaxies for the Megamaser Cosmology Project (MCP) allow accurate measurement of the mass of supermassive black holes (BH) in these galaxies. We present the Very Long Baseline Interferometry images and kinematics of water maser emission in six active galaxies: NGC 1194, NGC 2273, NGC 2960 (Mrk 1419), NGC 4388, NGC 6264 and NGC 6323. We use the Keplerian rotation curves of these six megamaser galaxies, plus a seventh previously published, to determine accurate enclosed masses within the central ~0.3pc of these galaxies, smaller than the radius of the sphere of influence of the central mass in all cases.
1695. The Megamaser Cosmology Project (MCP). IX.
ID:
ivo://CDS.VizieR/J/ApJ/834/52
Title:
The Megamaser Cosmology Project (MCP). IX.
Short Name:
J/ApJ/834/52
Date:
21 Oct 2021
Publisher:
CDS
Description:
As part of the Megamaser Cosmology Project, we present VLBI maps of nuclear water masers toward five galaxies. The masers originate in sub-parsec circumnuclear disks. For three of the galaxies, we fit Keplerian rotation curves to estimate their supermassive black hole (SMBH) masses, and determine (2.9+/-0.3)x10^6^M_{sun}_ for J0437+2456, (1.7+/-0.1)x10^7^M_{sun}_ for ESO 558-G009, and (1.1+/-0.2)x10^7^M_{sun}_ for NGC 5495. In the other two galaxies, Mrk 1029 and NGC 1320, the geometry and dynamics are more complicated and preclude robust black hole mass estimates. Including our new results, we compiled a list of 15 VLBI-confirmed disk maser galaxies with robust SMBH mass measurements. With this sample, we confirm the empirical relation of R_out_{propto}0.3M_SMBH_ reported in Wardle & Yusef-Zadeh (2012ApJ...750L..38W). We also find a tentative correlation between maser disk outer radii and Wide-Field Infrared Survey Explorer luminosity. We find no correlations of maser disk size with X-ray 2-10keV luminosity or [OIII] luminosity.
1696. The Megamaser Cosmology Project. X.
ID:
ivo://CDS.VizieR/J/ApJ/854/124
Title:
The Megamaser Cosmology Project. X.
Short Name:
J/ApJ/854/124
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present high-resolution (submas) Very Long Baseline Interferometry maps of nuclear H_2_O megamasers for seven galaxies. In UGC 6093, the well-aligned systemic masers and high-velocity masers originate in an edge-on, flat disk and we determine the mass of the central supermassive black holes (SMBH) to be M_SMBH_=2.58x10^7^M_{sun}_ (+/-7%). For J1346+5228, the distribution of masers is consistent with a disk, but the faint high-velocity masers are only marginally detected, and we constrain the mass of the SMBH to be in the range (1.5-2.0)x10^7^M_{sun}_. The origin of the masers in Mrk 1210 is less clear, as the systemic and high-velocity masers are misaligned and show a disorganized velocity structure. We present one possible model in which the masers originate in a tilted, warped disk, but we do not rule out the possibility of other explanations including outflow masers. In NGC 6926, we detect a set of redshifted masers, clustered within a parsec of each other, and a single blueshifted maser about 4.4pc away, an offset that would be unusually large for a maser disk system. Nevertheless, if it is a disk system, we estimate the enclosed mass to be M_SMBH_<4.8x10^7^M_{sun}_. For NGC 5793, we detect redshifted masers spaced about 1.4pc from a clustered set of blueshifted features. The orientation of the structure supports a disk scenario as suggested by Hagiwara+ (2001ApJ...560..119H). We estimate the enclosed mass to be M_SMBH_<1.3x10^7^M_{sun}_. For NGC 2824 and J0350-0127, the masers may be associated with parsec- or subparsec-scale jets or outflows.
1697. The MERLIN Archive
ID:
ivo://CDS.VizieR/B/merlin
Title:
The MERLIN Archive
Short Name:
B/merlin
Date:
21 Oct 2021
Publisher:
CDS
Description:
This database contains a log of MERLIN archive data since 1992 which have been partially reduced and are electronically available. It is managed and updated by the MERLIN staff. All data are taken using a single IF and correlated using 2-bit digitisation.
1698. The MIT-Green Bank 5GHz Survey
ID:
ivo://CDS.VizieR/VIII/52B
Title:
The MIT-Green Bank 5GHz Survey
Short Name:
VIII/52B
Date:
21 Oct 2021
Publisher:
CDS
Description:
The MIT-Green Bank 5GHz survey catalog was produced from four separate surveys with the National Radio Astronomy Observatory (NRAO) 91m transit telescope (Bennett et al., 1986ApJS...61....1B (MG1); Langston et al., 1990ApJS...72..621L (MG2); Griffith et al., 1990ApJS...74..129G (MG3); Griffith et al. 1991ApJS...75..801G (MG4)). The sky coverage of the various surveys is: 00h < RAB < 24h, -00d30'13" < DECB < +19d29'47" for MG1; 04h < RAJ < 21h, +17.0d < DECJ < +39d09' for MG2; 16h30m < RAB < 05h, +17d < DECB < +39d09' for MG3; and 15h30m < RAB < 02h30m, +37.00d < DECB < +50d58'48" for MG4; where RAB and DECB refer to B1950 coordinates, and RAJ and DECJ refer to J2000 coordinates. The catalog contains 20344 sources detected with a signal-to-noise ratio greater than 5 and 3836 possible detections (MG1) with a signal-to-noise ratio less than 5. Spectral indices are computed for MG1 sources also identified in the Texas 365MHz survey (Douglas et al. 1980), and for MG1-MG4 sources also identified in the NRAO 1400MHz Survey (Condon and Broderick 1985).
1699. The Miyun 232 MHz survey. I
ID:
ivo://CDS.VizieR/J/A+AS/99/545
Title:
The Miyun 232 MHz survey. I
Short Name:
J/A+AS/99/545
Date:
21 Oct 2021
Publisher:
CDS
Description:
This catalogue contains a new meter-wave survey of the sky region north of declination 30{deg}, carried out with the Miyun 232 MHz SSSynthesis Radio Telescope (MSRT) at HPBW 3.8' x 3.8' cosec(dec). Results from two fields are presented here; the fields are 8 degrees on a side, centered at 0041+41.2 and 0700+35.0. The accuracy of flux determination is limited by background fluctuation which is about 30 mJy. The catalogue is complete for sources with flux greater than 0.25 Jy. The total number of sources listed in the catalogue is 687.
1700. The mJIVE-20 catalog
ID:
ivo://CDS.VizieR/J/AJ/147/14
Title:
The mJIVE-20 catalog
Short Name:
J/AJ/147/14
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the description and early results of the mJy Imaging VLBA Exploration at 20cm (mJIVE-20). mJIVE-20 is a large project on the Very Long Baseline Array which is systematically inspecting a large sample of mJy radio sources, pre-selected from the Faint Images of the Radio Sky at Twenty cm (FIRST) survey made with the Very Large Array, to identify any compact emission that may be present. The survey is being undertaken using filler time on the VLBA, which utilizes short segments scheduled in bad weather and/or with a reduced number of antennas, during which no highly rated science projects can be scheduled. The newly available multifield capability of the VLBA makes it possible for us to inspect of the order of 100 sources per hour of observing time with a 6.75{sigma} detection sensitivity of approximately 1mJy/beam. The results of the mJIVE-20 survey are made publicly available as soon as the data are calibrated. After 18 months of observing, over 20000 FIRST sources have been inspected, with 4336 very long baseline interferometry detections. These initial results suggest that within the range 1-200mJy, fainter sources are somewhat more likely to be dominated by a very compact component than brighter sources. Over half of all arcsecond-scale mJy radio sources contain a compact component, although the fraction of sources that are dominated by milliarcsecond scale structure (where the majority of the arcsecond scale flux is recovered in the mJIVE-20 image) is smaller at around 30%-35%, increasing toward lower flux densities. Significant differences are seen depending on the optical classification of the source. Radio sources with a stellar/point-like counterpart in the Sloan Digital Sky Survey (SDSS) are more likely to be detected overall, but this detection likelihood appears to be independent of the arcsecond-scale radio flux density. The trend toward higher radio compactness for fainter sources is confined to sources that are not detected in SDSS or that have counterparts classified as galaxies. These results are consistent with a unification model of active galactic nuclei in which less luminous sources have on average slower radio jets, with lower Doppler suppression of compact core emission over a wider range of viewing angles.

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