- ID:
- ivo://CDS.VizieR/J/ApJ/869/142
- Title:
- Monitoring AGNs with H{beta} Asymmetry (MAHA). I.
- Short Name:
- J/ApJ/869/142
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have started a long-term reverberation mapping (RM) project using the Wyoming Infrared Observatory 2.3m telescope titled "Monitoring AGNs with H{beta} Asymmetry" (MAHA). The motivations of the project are to explore the geometry and kinematics of the gas responsible for complex H{beta} emission-line profiles, ideally leading to an understanding of the structures and origins of the broad-line region (BLR). Furthermore, such a project provides the opportunity to search for evidence of close binary supermassive black holes. We describe MAHA and report initial results from our first campaign, from 2016 December to 2017 May, highlighting velocity-resolved time lags for four active galactic nuclei (AGNs) with asymmetric H{beta} lines. We find that 3C120, Ark120, and Mrk6 display complex features different from the simple signatures expected for pure outflow, inflow, or a Keplerian disk. While three of the objects have been previously reverberation mapped, including velocity-resolved time lags in the cases of 3C120 and Mrk6, we report a time lag and corresponding black hole mass measurement for SBS1518+593 for the first time. Furthermore, SBS1518+593, the least asymmetric of the four, does show velocity-resolved time lags characteristic of a Keplerian disk or virialized motion more generally. Also, the velocity-resolved time lags of 3C120 have significantly changed since previously observed, indicating an evolution of its BLR structure. Future analyses of the data for these objects and others in MAHA will explore the full diversity of H{beta} lines and the physics of AGN BLRs.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/136/265
- Title:
- Monitoring compact radio sources at 2.5 + 8.2GHz
- Short Name:
- J/ApJS/136/265
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present light curves for 149 sources monitored with the Green Bank Interferometer. The light curves are at two radio frequencies (approximately 2.5 and 8.2GHz) and range from 3 to 15yr in length, covering the interval 1979-1996, and have a typical sampling of one flux density measurement every 2 days. Observations were made on a 2.4km baseline. Dual circular polarization was recorded over a 35MHz bandwidth at two frequencies in the S and X frequency bands. Until 1989 August (1989.7), the frequencies were 2.7GHz (S band) and 8.1GHz (X band); in 1989 September cryogenic receivers were installed, and the frequencies changed to 2.25GHz (S band) and 8.3GHz (X band).
- ID:
- ivo://CDS.VizieR/J/ApJ/542/673
- Title:
- Morphological types of galaxies in clusters
- Short Name:
- J/ApJ/542/673
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The morphological types of galaxies in nine clusters in the redshift range 0.1<~z<~0.25 are derived from very good seeing images taken at the North Optical Telescope (NOT) and the La Silla-Danish telescopes, with all galaxies at M_V_<-20 and within the central ~1Mpc^2^ area being classified. With the purpose of investigating the evolution of the fraction of different morphological types with redshift, we compare our results with the morphological content of nine distant clusters studied by the MORPHS group, five clusters observed with HST/WFPC2 at redshift z=0.2-0.3, and Dressler's large sample of nearby clusters.
- ID:
- ivo://CDS.VizieR/J/AJ/140/533
- Title:
- Morphologies of selected AGN
- Short Name:
- J/AJ/140/533
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the optical morphologies of candidate active galaxies identified at radio, X-ray, and mid-infrared wavelengths. We use the Advanced Camera for Surveys General Catalog (ACS-GC) to identify 372, 1360, and 1238 active galactic nucleus (AGN) host galaxies from Very Large Array, XMM-Newton, and Spitzer Space Telescope observations of the COSMOS field, respectively. We investigate both quantitative (GALFIT) and qualitative (visual) morphologies of these AGN host galaxies, split by brightness in their selection band.
- ID:
- ivo://CDS.VizieR/J/AJ/146/151
- Title:
- Morphology catalog of nearby galaxies from SDSS DR7
- Short Name:
- J/AJ/146/151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the statistical properties of a volume-limited sample of 7429 nearby (z=0.033-0.044) galaxies from the Sloan Digital Sky Survey Data Release 7. Our database includes morphology distribution as well as the structural and spectroscopic properties of each morphology type based on the recent remeasurements of spectral line strengths by Oh and collaborators. Our database does not include galaxies that are apparently smaller and flatter because morphology classification of them turned out to be difficult. Our statistics confirmed the up-to-date knowledge of galaxy populations, e.g., correlations between morphology and line strengths as well as the derived ages. We hope that this database will be useful as a reference.
- ID:
- ivo://CDS.VizieR/J/AJ/132/321
- Title:
- Morphology of narrow-line Seyfert 1 galaxies
- Short Name:
- J/AJ/132/321
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the nuclear morphology of a sample of narrow- and broad-line Seyfert 1 galaxies (NLS1s and BLS1s, respectively) based on broadband images in the Hubble Space Telescope archives. In our previous study we found that large-scale stellar bars at >1kpc from the nucleus are more common in NLS1s than BLS1s. In this paper we find that NLS1s preferentially have grand-design dust spirals within ~1kpc of their centers. We also find that NLS1s have a higher fraction of nuclear star-forming rings than BLS1s. We find that many of the morphological differences are due to the presence or absence of a large-scale stellar bar within the spiral host galaxy. In general, barred Seyfert 1 galaxies tend to have grand-design dust spirals at their centers, confirming the results of other researchers. The high fraction of grand-design nuclear dust spirals and stellar nuclear rings observed in NLS1s' host galaxies suggests a means for efficient fueling of their nuclei to support their high Eddington ratios.
- ID:
- ivo://CDS.VizieR/J/ApJ/721/98
- Title:
- Morphology of 70um COSMOS galaxies
- Short Name:
- J/ApJ/721/98
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze the morphological properties of a large sample of 1503 70um selected galaxies in the COSMOS field spanning the redshift range 0.01<z<3.5 with a median redshift of 0.5 and an infrared luminosity range of 10^8^<L_IR_(8-1000um)<10^14^L_{sun}_ with a median luminosity of 10^11.4^L_{sun}_. In general, these galaxies are massive, with a stellar mass range of 10^10^-10^12^M_{sun}_, and luminous, with -25<M_K_<-20. The precise fraction of mergers in any given L_IR_ bin varies by redshift due to sources at z>1 being difficult to classify and subject to the effects of bandpass shifting; therefore, these numbers can only be considered lower limits. At z<1, where the morphological classifications are most robust, major mergers clearly dominate the ULIRG population (~50%-80%) and are important for the LIRG population (~25%-40%). At z>1, the fraction of major mergers is lower, but is at least 30%-40% for ULIRGs. In a comparison of our visual classifications with several automated classification techniques we find general agreement; however, the fraction of identified mergers is underestimated due to automated classification methods being sensitive to only certain timescales of a major merger. The distribution of the U-V color of the galaxies in our sample peaks in the green valley (<U-V>=1.1) with a large spread at bluer and redder colors and with the major mergers peaking more strongly in the green valley than the rest of the morphological classes.
- ID:
- ivo://CDS.VizieR/J/ApJ/698/1682
- Title:
- Most luminous dusty galaxies
- Short Name:
- J/ApJ/698/1682
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A summary of mid-infrared continuum luminosities arising from dust is given for very luminous galaxies, L_IR_>10^12^L_{sun}_, with 0.005<z<3.2 containing active galactic nuclei (AGNs), including 115 obscured AGNs and 60 unobscured (type 1) AGNs. All sources have been observed with the Spitzer Infrared Spectrograph. Obscured AGNs are defined as having optical depth {tau}>0.7 in the 9.7um silicate absorption feature (i.e., half of the continuum is absorbed) and having equivalent width of the 6.2um polycyclic aromatic hydrocarbon feature <0.1um (to avoid sources with a significant starburst component). Unobscured AGNs are defined as those that show silicate in emission. Luminosity {nu}L_{nu}_(8um) for the most luminous obscured AGNs is found to scale as (1+z)^2.6^ to z=2.8. For unobscured AGNs, the scaling with redshift is similar, but luminosities {nu}L_{nu}_(8um) are approximately three times greater for the most luminous sources. Using both obscured and unobscured AGNs having total infrared fluxes from the Infrared Astronomical Satellite, empirical relations are found between {nu}L_{nu}_(8um) and L_IR_.
- ID:
- ivo://CDS.VizieR/J/ApJ/775/92
- Title:
- MQS III: AGNs behind LMC and SMC
- Short Name:
- J/ApJ/775/92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Magellanic Quasars Survey (MQS) has now increased the number of quasars known behind the Magellanic Clouds by almost an order of magnitude. All survey fields in the Large Magellanic Cloud (LMC) and 70% of those in the Small Magellanic Cloud (SMC) have been observed. The targets were selected from the third phase of the Optical Gravitational Lensing Experiment (OGLE-III) based on their optical variability, mid-IR, and/or X-ray properties. We spectroscopically confirmed 758 quasars (565 in the LMC and 193 in the SMC) behind the clouds, of which 94% (527 in the LMC and 186 in the SMC) are newly identified. The MQS quasars have long-term (12yr and growing for OGLE), high-cadence light curves, enabling unprecedented variability studies of quasars. The MQS quasars also provide a dense reference grid for measuring both the internal and bulk proper motions of the clouds, and 50 quasars are bright enough (I<~18mag) for absorption studies of the interstellar/intergalactic medium of the clouds.
- ID:
- ivo://CDS.VizieR/J/ApJS/107/19
- Title:
- MRC/1Jy Radio source survey. I.
- Short Name:
- J/ApJS/107/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the first in a series of papers discussing the properties of a complete set of radio sources selected near S408=1Jy. We present optical or infrared identifications for a sample of 452 radio galaxies. The sources were selected from the 408MHz Molonglo Reference Catalog, restricted only by flux density and position on the sky, as follows: S408>0.95Jy and -30<decl.(1950)<-20, and 9h20m<R.A.(1950)<14h4m or 20h20m<R.A.(1950)<6h14m. This complete sample, the MRC/1 Jy survey, contains 558 radio galaxies or quasars, of which six are occulted by bright stars or galaxies and two are multiple confused sources. Of the remaining 550 sources, 527, or 96%, are identified to an r magnitude of 25, and eight additional sources are identified to K=19. Of the 17 unocculted objects that remain unidentified, 15 are sources for which we have either poor radio maps or inadequate optical/IR images. This paper presents finding charts and astrometric positions for the 452 sources that are not identified as either quasars or BL Lacertae objects. Magnitudes in the r passband accurate to typically 0.1mag are given for 353 of the radio galaxy identifications. Redshifts for 268 of the galaxies are also listed; these have been derived from 450 spectroscopic observations. The radio observations, quasar and BL Lac identifications, spectroscopy, and near-IR images will be presented in subsequent papers in this series.