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11. A catalogue of BL Lacertae objects
ID:
ivo://CDS.VizieR/J/MNRAS/277/1477
Title:
A catalogue of BL Lacertae objects
Short Name:
J/MNRAS/277/1477
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalogue of 233 BL Lacertae objects compiled through an extensive bibliographic search updated to mid-1995. A large fraction of the sources listed in the catalogue belongs to well-defined samples and can be used for statistical purposes. A smaller fraction consists of miscellaneous (but confirmed) BL Lacs and of objects classified as BL Lac candidates. We discuss the selection criteria of the different samples, report the discovery of two previously unnoticed BL Lacs in the Palomar-Green survey, and comment on the possible association of some of the still unidentified high galactic latitude gamma-ray (EGRET, see Thompson et al., =1995ApJS..101..259T) sources with BL Lacs. Some statistical properties of the catalogue are also briefly discussed.
12. A catalogue of cross-matched radio/infrared/X-ray sources
ID:
ivo://CDS.VizieR/V/138
Title:
A catalogue of cross-matched radio/infrared/X-ray sources
Short Name:
V/138
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalog of cross-correlated radio, infrared and X-ray sources using a very restrictive selection criteria with an IDL-based code developed by us. The significance of the observed coincidences was evaluated through Monte Carlo simulations of synthetic sources following a well-tested protocol. We found 3320 coincident radio/X-ray sources with a high statistical significance characterized by the sum of error-weighted coordinate differences. For 997 of them, 2MASS counterparts were found. The percentage of chance coincidences is less than 1%. X-ray hardness ratios of well-known populations of objects were used to provide a crude representation of their X-ray spectrum and to make a preliminary diagnosis of the possible nature of unidentified X-ray sources. The results support the fact that the X-ray sky is largely dominated by Active Galactic Nuclei at high galactic latitudes (|b|>=10deg). At low galactic latitudes (|b|<=10deg) most of unidentified X-ray sources (~94%) lie at |b|>=2deg. This result suggests that most of the unidentified sources found toward the Milky Way plane are galactic objects. Well-known and unidentified sources were classified in different tables with their corresponding radio/infrared and X-ray properties. These tables are intended as a useful tool for researchers interested in particular identifications.
13. Accurate OH maser positions from SPLASH. III.
ID:
ivo://CDS.VizieR/J/ApJS/247/5
Title:
Accurate OH maser positions from SPLASH. III.
Short Name:
J/ApJS/247/5
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present high spatial resolution observations of ground-state OH masers achieved with the Australia Telescope Compact Array (ATCA). These observations targeted 253 pointing centers containing OH maser candidates at all four ground-state OH transitions identified in the Southern Parkes Large-Area Survey in Hydroxyl (SPLASH) across 96deg^2^ of the southern Galactic plane (332{deg}<l<334{deg} and -2{deg}<b<+2{deg}, 344{deg}<l<355{deg} and -2{deg}<b<+2{deg}, 358{deg}<l<4{deg} and +2{deg}<b<+6{deg}, 5{deg}<l<10{deg} and -2{deg}<b<+2{deg}). We detect maser emission toward 236 fields and suggest that 7 out of 17 nondetections are due to the slightly lower sensitivity of the ATCA observations, combined with some temporal variability. The superior resolution provided by the ATCA data has allowed us to identify 362 OH maser sites in the 236 target fields. Almost half (160 of 362) of these masers have been detected for the first time. Comparison between these 362 maser sites and information presented in the literature allowed us to categorize 238 sites as evolved star sites (66%), 63 as star formation (17%), 8 as supernova remnants, and 53 as unknown maser sites (15%). We present an analysis of the OH masers across the full SPLASH survey range (176deg^2^) and find that the detection rate of 1.7GHz radio continuum sources (18%) is lower than that previously found at 8.2 and 9.2GHz (38%). We also find that the velocity separations of evolved star sites with symmetric 1612MHz maser profiles are generally smaller than those with asymmetric profiles.
14. Accurate OH maser positions. II. The GC.
ID:
ivo://CDS.VizieR/J/ApJS/239/15
Title:
Accurate OH maser positions. II. The GC.
Short Name:
J/ApJS/239/15
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present high spatial resolution observations of ground-state OH masers achieved using the Australia Telescope Compact Array (ATCA). These observations were conducted toward 171 pointing centers where OH maser candidates were identified previously in the Southern Parkes Large-Area Survey in Hydroxyl (SPLASH) toward the Galactic center region between Galactic longitudes of 355* and 5* and Galactic latitudes of -2{deg} and +2{deg}. We detect maser emission toward 162 target fields and suggest that six out of nine nondetections are due to intrinsic variability. Due to the superior spatial resolution of the follow-up ATCA observations, we have identified 356 OH maser sites in the 162 target fields with maser detections. Almost half (161 of 356) of these maser sites have been detected for the first time in these observations. After comparing the positions of these 356 maser sites to the literature, we find that 269 (76%) sites are associated with evolved stars (two of which are PNe), 31 (9%) are associated with star formation, and four are associated with supernova remnants; we were unable to determine the origin of the remaining 52 (15%) sites. Unlike the pilot region, the infrared colors of evolved star sites with symmetric maser profiles in the 1612MHz transition do not show obvious differences compared with those of evolved star sites with asymmetric maser profiles.
15. Accurate water maser positions from HOPS
ID:
ivo://CDS.VizieR/J/MNRAS/442/2240
Title:
Accurate water maser positions from HOPS
Short Name:
J/MNRAS/442/2240
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on high spatial resolution water maser observations, using the Australia Telescope Compact Array, towards water maser sites previously identified in the H2O southern Galactic Plane Survey (HOPS) within the area covering Galactic coordinates from l=290 to l=30 and b=-0.5 to b=+0.5. Of the 540 maser sites identified in the single-dish observations of Walsh et al. (2011MNRAS.416.1764W, Cat. J/MNRAS/416/1764), we detect emission in all but 31 fields. These maser sites together comprise 2790 individual spectral features (maser spots), with brightnesses ranging from 0.06Jy to 576Jy and with velocities ranging from -238.5 to +300.5km/s. Based on a definition of maser site size of 4-arcsec (except for G000.667+0.028, also known as Sgr B2, which we treat as a special case), we identify 631 maser sites. We have compared the positions of these sites to the literature to associate the sites with astrophysical objects. We identify 433 (69%) with star formation, 121 (19%) with evolved stars and 77 (12%) as unknown. Comparing the properties of maser sites of different origins, we find that those associated with evolved stars tend to have more maser spots and have smaller angular sizes than those associated with star formation. We present evidence that maser sites associated with evolved stars show an increased likelihood of having a velocity range between 15 and 35 km/s compared to other maser sites. We suggest this is because many of these maser sites are associated with the circumstellar shells of the evolved stars, which are expanding at these velocities. Of the 31 non-detections, we conclude they were not detected due to intrinsic variability and confirm previous results showing that such variable masers tend to be weaker and have simpler spectra with fewer peaks. Of the small number of maser sites showing linear features, we find evidence for lines that are both perpendicular and parallel to known outflows, suggesting that in star formation, H_2_O maser origins may be as varied and as complex as those of class II methanol masers.
16. Acetaldehyde CH_2_DCOH and CH_3_COD
ID:
ivo://CDS.VizieR/J/A+A/624/A70
Title:
Acetaldehyde CH_2_DCOH and CH_3_COD
Short Name:
J/A+A/624/A70
Date:
21 Oct 2021
Publisher:
CDS
Description:
Detection of deuterated species may provide information on the evolving chemistry in the earliest phases of star-forming regions. For molecules with two isomeric forms of the same isotopic variant, gas-phase and solid-state formation pathways can be differentiated using their abundance ratio. Spectroscopic databases for astrophysical purposes are built for the two mono deuterated isomeric species CH_2_DCOH and CH_3_COD of the complex organic molecule acetaldehyde. These databases can be used to search and detect these two species in astrophysical surveys, retrieving their column density and therefore abundances. Submillimeter wave and terahertz transitions were measured for mono deuterated acetaldehyde CH2DCOH which is a non-rigid species displaying internal rotation of its asymmetrical CH_2_D methyl group. An analysis of a dataset consisting of previously measured microwave data and the newly measured transition was carried out with a model accounting for the large amplitude torsion. The frequencies of 2556 transitions are reproduced with a unitless standard deviation of 2.3 yielding various spectroscopic constants. Spectroscopic databases for astrophysical purposes were built for CH_2_DCOH using the results of the present analysis and for CH_3_COD using the results of a previous spectroscopic investigation. These two species were both searched for and are detected toward a low-mass star-forming region. We report the first detection of CH2DCOH (93 transitions) and the detection of CH_3_COD (43 transitions) species in source B of the IRAS 16293-2422 young stellar binary system located in the {rho} Ophiuchus cloud region, using the publicly available ALMA Protostellar Interferometric Line Survey.
17. A cluster of compact radio sources in W40
ID:
ivo://CDS.VizieR/J/AJ/140/968
Title:
A cluster of compact radio sources in W40
Short Name:
J/AJ/140/968
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present deep 3.6 cm radio continuum observations of the HII region W40 obtained using the Very Large Array (VLA) in its A and B configurations. We detect a total of 20 compact radio sources in a region of 4'x4', with 11 of them concentrated in a band with 30" of extent. We also present JHK photometry of the W40 cluster taken with the QUIRC instrument on the University of Hawaii 2.2m telescope. These data reveal that 15 of the 20 VLA sources have infrared counterparts, and 10 show radio variability with periods less than 20 days. Based on these combined radio and IR data, we propose that eight of the radio sources are candidate ultracompact HII regions, seven are likely to be young stellar objects, and two may be shocked interstellar gas.
18. A complete sample of broad-line AGN from SDSS-DR7
ID:
ivo://CDS.VizieR/J/ApJS/243/21
Title:
A complete sample of broad-line AGN from SDSS-DR7
Short Name:
J/ApJS/243/21
Date:
21 Oct 2021
Publisher:
CDS
Description:
A new, complete sample of 14584 broad-line active galactic nuclei (AGNs) at z<0.35 is presented, which are uncovered homogeneously from the complete database of galaxies and quasars observed spectroscopically in the Sloan Digital Sky Survey Seventh Data Release. The stellar continuum is properly removed for each spectrum with significant host absorption line features, and careful analyses of the emission line spectra, particularly in the H{alpha} and H{beta} wavebands, are carried out. The broad Balmer emission line, particularly H{alpha}, is used to indicate the presence of an AGN. The broad H{alpha} lines have luminosities in a range of 10^38.5^-10^44.3^erg/s, and line widths (FWHMs) of 500-34000km/s. The virial black hole masses, estimated from the broad-line measurements, span a range of 10^5.1^-10^10.3^M_{sun}_, and the Eddington ratios vary from -3.3 to 1.3 in logarithmic scale. Other quantities such as multiwavelength photometric properties and flags denoting peculiar line profiles are also included in this catalog. We describe the construction of this catalog and briefly discuss its properties. The catalog is publicly available online. This homogeneously selected AGN catalog, along with the accurately measured spectral parameters, provides the most updated, largest AGN sample data, which will enable further comprehensive investigations of the properties of the AGN population in the low-redshift universe.
19. A CO survey of young planetary nebulae
ID:
ivo://CDS.VizieR/J/ApJS/160/272
Title:
A CO survey of young planetary nebulae
Short Name:
J/ApJS/160/272
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the results of a sensitive survey of young planetary nebulae in the CO J=2-1 line that significantly increases the available data on warm, dense, molecular gas in the early phases of planetary nebula formation. The observations were made using the IRAM 30m telescope with the 3x3 pixel Heterodyne Receiver Array (HERA). The array provides an effective means of discriminating the CO emission of planetary nebulae in the Galactic plane from contaminating emission of interstellar clouds along the line of sight. A total of 110 planetary nebulae were observed in the survey, and 40 were detected. The results increase the number of young planetary nebulae with known CO emission by approximately a factor of 2. The CO spectra yield radial velocities for the detected nebulae, about half of which have uncertain or no velocity measurements at optical wavelengths. The CO profiles range from parabolic to double-peaked, tracing the evolution of structure in the molecular gas. The line widths are significantly larger than on the asymptotic giant branch, and many of the lines show extended wings, which probably result from the effects on the envelopes of high-velocity jets.
20. ACS J1149.5+2223 LOFAR and VLA images
ID:
ivo://CDS.VizieR/J/A+A/650/A44
Title:
ACS J1149.5+2223 LOFAR and VLA images
Short Name:
J/A+A/650/A44
Date:
22 Feb 2022
Publisher:
CDS
Description:
Radio halos and relics are Mpc-scale diffuse radio sources in galaxy clusters, which have a steep spectral index {alpha}>1 (defined as S{prop.to}{nu}^-{alpha}^). It has been proposed that halos and relics arise from particle acceleration induced by turbulence and weak shocks that are injected into the intracluster medium (ICM) during mergers. MACS J1149.5+2223 is a high-redshift (z=0.544) galaxy cluster possibly hosting a radio halo and a relic. We analysed LOw Frequency Array (LOFAR), Giant Metrewave Radio Telescope, and Karl G. Jansky Very Large Array (JVLA) radio data at 144, 323, and 1500MHz, respectively. In addition, we analysed archival Chandra X-ray data to characterise the thermal and non-thermal properties of the cluster. We obtained radio images at different frequencies to investigate the spectral properties of the radio halo. We used Chandra X-ray images to constrain the thermal properties of the cluster and to search for discontinuities (due to cold fronts or shock fronts) in the surface brightness of the ICM. By combining radio and X-ray images, we carried out a point-to-point analysis to study the connection between the thermal and non-thermal emission. We measured a steep spectrum of the halo, which can be described by a power-law with {alpha}=1.49+/-0.12 between 144 and 1500MHz. The radio surface brightness distribution across the halo is found to correlate with the X-ray brightness of the ICM. The derived correlation shows a sub-linear slope in the range 0.4-0.6. We also report two possible cold fronts in north-east and north-west, but deeper X-ray observations are required to firmly constrain the properties of the upstream emission. We show that the combination of high-redshift, steep radio spectrum, and sub-linear radio-X scaling of the halo rules out hadronic models. An old (~1Gyr ago) major merger likely induced the formation of the halo through stochastic re-acceleration of relativistic electrons. We suggest that the two possible X-ray discontinuities may be part of the same cold front. In this case, the coolest gas pushed towards the north-west might be associated with the cool core of a sub-cluster involved in the major merger. The peculiar orientation of the south-east relic might indicate a different nature of this source and requires further investigation.