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- ID:
- ivo://CDS.VizieR/J/ApJ/840/21
- Title:
- FIR data of IR-bright dust-obscured galaxies (DOGs)
- Short Name:
- J/ApJ/840/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the star-forming activity of a sample of infrared (IR)-bright dust-obscured galaxies (DOGs) that show an extreme red color in the optical and IR regime, (i-[22])_AB_>7.0. Combining an IR-bright DOG sample with the flux at 22{mu}m>3.8mJy discovered by Toba & Nagao (2016ApJ...820...46T) with the IRAS faint source catalog version 2 and AKARI far-IR (FIR) all-sky survey bright source catalog version 2, we selected 109 DOGs with FIR data. For a subsample of seven IR-bright DOGs with spectroscopic redshifts (0.07<z<1.0) that were obtained from the literature, we estimated their IR luminosity, star formation rate (SFR), and stellar mass based on the spectral energy distribution fitting. We found that (1) the WISE 22{mu}m luminosity at the observed frame is a good indicator of IR luminosity for IR-bright DOGs and (2) the contribution of the active galactic nucleus to IR luminosity increases with IR luminosity. By comparing the stellar mass and SFR relation for our DOG sample and the literature, we found that most of the IR-bright DOGs lie significantly above the main sequence of star-forming galaxies at similar redshift, indicating that the majority of IRAS- or AKARI-detected IR-bright DOGs are starburst galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJS/226/19
- Title:
- FIR spectra of AGNs from Herschel
- Short Name:
- J/ApJS/226/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a coherent database of spectroscopic observations of far-IR fine-structure lines from the Herschel/Photoconductor Array Camera and Spectrometer (PACS) archive for a sample of 170 local active galactic nuclei (AGNs), plus a comparison sample of 20 starburst galaxies and 43 dwarf galaxies. Published Spitzer/IRS and Herschel/SPIRE line fluxes are included to extend our database to the full 10-600{mu}m spectral range. The observations are compared to a set of Cloudy photoionization models to estimate the above physical quantities through different diagnostic diagrams. We confirm the presence of a stratification of gas density in the emission regions of the galaxies, which increases with the ionization potential of the emission lines. The new [OIV]_25.9um_/[OIII]_88um_ versus [NeIII]_15.6um_/[NeII]_12.8um_ diagram is proposed as the best diagnostic to separate (1) AGN activity from any kind of star formation and (2) low-metallicity dwarf galaxies from starburst galaxies. Current stellar atmosphere models fail to reproduce the observed [OIV]_25.9um_/[OIII]_88um_ ratios, which are much higher when compared to the predicted values. Finally, the ([NeIII]_15.6um_+[NeII]_12.8um_)/([SIV]_10.5um_+[SIII]_18.7um_) ratio is proposed as a promising metallicity tracer to be used in obscured objects, where optical lines fail to accurately measure the metallicity. The diagnostic power of mid- to far-infrared spectroscopy shown here for local galaxies will be of crucial importance to study galaxy evolution during the dust-obscured phase at the peak of the star formation and black hole accretion activity (1<z<4). This study will be addressed by future deep spectroscopic surveys with present and forthcoming facilities such as the James Webb Space Telescope, the Atacama Large Millimeter/submillimeter Array, and the Space Infrared telescope for Cosmology and Astrophysics.
- ID:
- ivo://CDS.VizieR/J/ApJ/715/429
- Title:
- First Fermi-LAT AGN catalog (1LAC)
- Short Name:
- J/ApJ/715/429
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first catalog of active galactic nuclei (AGNs) detected by the Large Area Telescope (LAT), corresponding to 11 months of data collected in scientific operation mode. The First LAT AGN Catalog (1LAC) includes 671 {gamma}-ray sources located at high Galactic latitudes (|b|>10{deg}) that are detected with a test statistic greater than 25 and associated statistically with AGNs. Some LAT sources are associated with multiple AGNs, and consequently, the catalog includes 709 AGNs, comprising 300 BL Lacertae objects, 296 flat-spectrum radio quasars, 41 AGNs of other types, and 72 AGNs of unknown type. We also classify the blazars based on their spectral energy distributions as archival radio, optical, and X-ray data permit. In addition to the formal 1LAC sample, we provide AGN associations for 51 low-latitude LAT sources and AGN "affiliations" (unquantified counterpart candidates) for 104 high-latitude LAT sources without AGN associations.
- ID:
- ivo://CDS.VizieR/J/ApJ/699/L43
- Title:
- FIRST-NVSS-SDSS AGN sample catalog
- Short Name:
- J/ApJ/699/L43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Radio outflows of active galactic nuclei (AGNs) are invoked in cosmological models as a key feedback mechanism in the latest phases of massive galaxy formation. Recently, it has been suggested that the two major radio AGN populations-the powerful high-excitation, and the weak low-excitation radio AGNs (HERAGN and LERAGN, respectively)-represent two earlier and later stages of massive galaxy buildup. To test this, here we make use of a local (0.04<z<0.1) sample of ~500 radio AGNs with available optical spectroscopy, drawn from the FIRST, NVSS, SDSS, and 3CRR surveys.
- ID:
- ivo://CDS.VizieR/J/ApJ/787/151
- Title:
- Fitted jet components in BL Lacertae
- Short Name:
- J/ApJ/787/151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Parsec-scale VLBA images of BL Lac at 15 GHz show that the jet contains a permanent quasi-stationary emission feature 0.26 mas (0.34 pc projected) from the core, along with numerous moving features. In projection, the tracks of the moving features cluster around an axis at a position angle of -166.6{deg} that connects the core with the standing feature. The moving features appear to emanate from the standing feature in a manner strikingly similar to the results of numerical two-dimensional relativistic magneto-hydrodynamic (RMHD) simulations in which moving shocks are generated at a recollimation shock (RCS). Because of this, and the close analogy to the jet feature HST-1 in M87, we identify the standing feature in BL Lac as an RCS. We assume that the magnetic field dominates the dynamics in the jet, and that the field is predominantly toroidal. From this we suggest that the moving features are compressions established by slow and fast mode magneto-acoustic MHD waves. We illustrate the situation with a simple model in which the slowest moving feature is a slow-mode wave, and the fastest feature is a fast-mode wave. In the model, the beam has Lorentz factor {Gamma}_beam_^gal^~3.5 in the frame of the host galaxy and the fast mode wave has Lorentz factor {Gamma}_Fwave_^beam^~1.6 in the frame of the beam. This gives a maximum apparent speed for the moving features, {beta}_app_=v_app_/c=10. In this model the Lorentz factor of the pattern in the galaxy frame is approximately three times larger than that of the beam itself.
- ID:
- ivo://CDS.VizieR/J/ApJ/704/1570
- Title:
- Fitting LINERs within the AGN family
- Short Name:
- J/ApJ/704/1570
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we study the nuclear obscuration of galaxies hosting low ionization narrow emission regions (LINERs) based on their X-ray and optical emission. They show column densities at soft energies (0.5-2keV) mostly related to the diffuse emission around the active galactic nucleus (AGN), showing a correlation with the optical extinction. Column densities at hard energies (2-10keV) seem to be much higher than what would be expected from the optical extinction. They might be associated with the inner regions of the AGN, buried at optical wavelengths.
- ID:
- ivo://CDS.VizieR/J/A+A/410/813
- Title:
- 2001 Flare of Mkn 421 in gamma-ray
- Short Name:
- J/A+A/410/813
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the first months of 2001 the AGN Mkn 421 showed highly variable, strong TeV activity at flux levels frequently exceeding 1 Crab. Here we present the light curve and energy spectrum of Mkn 421 as measured with the HEGRA stand alone telescope CT1. Around 30% of the data were taken under moonlight conditions. The spectrum shows a significant exponential energy cutoff at around 3.4 TeV. The results from the dark night- and the moon data are in excellent agreement with each other. A significant spectral shape variation depending on the flux level has been found. The TeV light curve is also found to be highly correlated with the X-ray light curve of the RXTE/ASM satellite, showing no significant time lag larger than 0.2d. The derived correlation coefficient of 0.83 corresponds to a 5.2{sigma} significance.
- ID:
- ivo://CDS.VizieR/J/ApJ/846/34
- Title:
- Flaring gamma-ray sources; LAT 7.4yr (2FAV)
- Short Name:
- J/ApJ/846/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the second catalog of flaring gamma-ray sources (2FAV) detected with the Fermi All-sky Variability Analysis (FAVA), a tool that blindly searches for transients over the entire sky observed by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. With respect to the first FAVA catalog, this catalog benefits from a larger data set, the latest LAT data release (Pass 8), as well as from an improved analysis that includes likelihood techniques for a more precise localization of the transients. Applying this analysis to the first 7.4 years of Fermi observations, and in two separate energy bands 0.1-0.8GeV and 0.8-300GeV, a total of 4547 flares were detected with significance greater than 6{sigma} (before trials), on the timescale of one week. Through spatial clustering of these flares, 518 variable gamma-ray sources were identified. Based on positional coincidence, likely counterparts have been found for 441 sources, mostly among the blazar class of active galactic nuclei. For 77 2FAV sources, no likely gamma-ray counterpart has been found. For each source in the catalog, we provide the time, location, and spectrum of each flaring episode. Studying the spectra of the flares, we observe a harder-when-brighter behavior for flares associated with blazars, with the exception of BL Lac flares detected in the low-energy band. The photon indexes of the flares are never significantly smaller than 1.5. For a leptonic model, and under the assumption of isotropy, this limit suggests that the spectrum of freshly accelerated electrons is never harder than p~2.
- ID:
- ivo://CDS.VizieR/J/A+AS/106/29
- Title:
- Flat-spectrum radio sources at 327 MHz
- Short Name:
- J/A+AS/106/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
