- ID:
- ivo://CDS.VizieR/J/A+A/566/A59
- Title:
- 3.5 and 1.3mm polarimetric survey of Northern AGNs
- Short Name:
- J/A+A/566/A59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Short millimeter observations of radio-loud active galactic nuclei (AGN) offer an excellent opportunity to study the physics of their synchrotron-emitting relativistic jets from where the bulk of radio and millimeter emission is radiated. On one hand, AGN jets and their emission cores are significantly less affected by Faraday rotation and depolarization than at longer wavelengths. On the other hand, the millimeter emission of AGN is dominated by the compact innermost regions in the jets, where the jet cannot be seen at longer wavelengths due to synchrotron opacity. We present the first simultaneous dual frequency 86GHz and 229GHz polarimetric survey of all four Stokes parameters for a large sample of 211 radio-loud active galactic nuclei, designed to be flux limited at 1Jy at 86GHz. Most of the observations were made in mid-August 2010 using the XPOL polarimeter on the IRAM 30m millimetric radio telescope.
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- ID:
- ivo://CDS.VizieR/J/ApJ/827/118
- Title:
- A new reverberation mapping campaign on NGC 5548
- Short Name:
- J/ApJ/827/118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 5548 is the best-observed reverberation-mapped active galactic nucleus with long-term, intensive monitoring. Here we report results from a new observational campaign between 2015 January and July. We measure the centroid time lag of the broad H{beta} emission line with respect to the 5100{AA} continuum and obtain {tau}_cent_=7.20_-0.35_^+1.33^days in the rest frame. This yields a black hole mass of M.=8.71_-2.61_^+3.21^x10^7^M_{sun}_ using a broad H{beta} line dispersion of 3124+/-302km/s and a virial factor of f_BLR_=6.3+/-1.5 for the broad-line region (BLR), consistent with the mass measurements from previous H{beta} campaigns. The high-quality data allow us to construct a velocity-binned delay map for the broad H{beta} line, which shows a symmetric response pattern around the line center, a plausible kinematic signature of virialized motion of the BLR. Combining all the available measurements of H{beta} time lags and the associated mean 5100{AA} luminosities over 18 campaigns between 1989 and 2015, we find that the H{beta} BLR size varies with the mean optical luminosity, but, interestingly, with a possible delay of 2.35_-1.25_^+3.47^ years. This delay coincides with the typical BLR dynamical timescale of NGC 5548, indicating that the BLR undergoes dynamical changes, possibly driven by radiation pressure.
- ID:
- ivo://CDS.VizieR/J/ApJ/724/1336
- Title:
- An extragalactic ^12^CO J=3-2 survey
- Short Name:
- J/ApJ/724/1336
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of a ^12^COJ=3-2 survey of 125 nearby galaxies obtained with the 10m Heinrich Hertz Telescope, with the aim to characterize the properties of warm and dense molecular gas in a large variety of environments. With an angular resolution of 22", ^12^CO3-2 emission was detected in 114 targets. Based on 61 galaxies observed with equal beam sizes the ^12^CO3-2/1-0 integrated line intensity ratio R_31_ is found to vary from 0.2 to 1.9, with an average value of 0.81. No correlations are found for R_31_ to Hubble-type and far-infrared luminosity. Possible indications for a correlation with inclination angle and the 60um/100um color temperature of the dust are not significant. Higher R_31_ ratios than in "normal" galaxies, hinting at enhanced molecular excitation, may be found in galaxies hosting active galactic nuclei. Even higher average values are determined for galaxies with bars or starbursts, the latter being identified by the ratio of infrared luminosity versus isophotal area, log [(L_FIR_/L_{sun}_)/(D^2^_25_/kpc^2^)]>7.25. (U)LIRGs are found to have the highest averaged R_31_ value. This may be a consequence of particularly vigorous star formation activity, triggered by galaxy interaction and merger events.
- ID:
- ivo://CDS.VizieR/J/AJ/161/196
- Title:
- An optical overview of blazars with LAMOST. I.
- Short Name:
- J/AJ/161/196
- Date:
- 16 Mar 2022 11:51:00
- Publisher:
- CDS
- Description:
- The extragalactic {gamma}-rays sky observed by the Fermi Large Area Telescope (LAT) is dominated by blazars. In the fourth release of the Fermi LAT Point Source Catalog (4FGL) are sources showing a multifrequency behavior similar to that of blazars but lacking an optical spectroscopic confirmation of their nature, known as blazar candidates of uncertain type (BCUs). We aim at confirming the blazar nature of BCUs and test if new optical spectroscopic observations can reveal spectral features, allowing us to get a redshift estimate for known BL Lac objects. We also aim to search for and discover changing-look blazars (i.e., blazars that show a different classification at different epochs). We carry out an extensive search for optical spectra available in the Large Sky Area Multi-object Fibre Spectroscopic Telescope (LAMOST) Data Release 5 (DR5) archive. We select sources out of the 4FGL catalog, the list of targets from our follow-up spectroscopic campaign of unidentified or unassociated {gamma}-ray sources, and the multifrequency catalog of blazars: the Roma-BZCAT. We select a total of 392 spectra. We also compare some of the LAMOST spectra with those available in the literature. We classify 20 BCUs confirming their blazar-like nature. Then we obtain 15 new redshift estimates for known blazars. We discover 26 transitional (i.e., changing-look) blazars that changed their classification. Finally, we are able to confirm the blazar-like nature of six BL Lac candidates. All remaining sources analyzed agree with previous classifications. BL Lac objects are certainly the most elusive type of blazars in the {gamma}-ray extragalactic sky.
- ID:
- ivo://CDS.VizieR/J/ApJ/727/83
- Title:
- A panchromatic study of BLAST counterparts
- Short Name:
- J/ApJ/727/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carry out a multi-wavelength study of individual galaxies detected by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) and identified at other wavelengths, using data spanning the radio to the ultraviolet (UV). We develop a Monte Carlo method to account for flux boosting, source blending, and correlations among bands, which we use to derive deboosted far-infrared (FIR) luminosities for our sample. We estimate total star-formation rates (SFRs) for BLAST counterparts with z<=0.9 by combining their FIR and UV luminosities. We assess that about 20% of the galaxies in our sample show indication of a type 1 active galactic nucleus, but their submillimeter emission is mainly due to star formation in the host galaxy. We compute stellar masses for a subset of 92 BLAST counterparts; these are relatively massive objects, with a median mass of ~10^11^M_{sun}_, which seem to link the 24um and Submillimetre Common-User Bolometer Array (SCUBA) populations, in terms of both stellar mass and star formation activity.
- ID:
- ivo://CDS.VizieR/J/A+A/617/A118
- Title:
- APM 08279+5255 optical-to-UV spectrum
- Short Name:
- J/A+A/617/A118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of the rest-frame optical-to-UV spectrum of APM 08279+5255, a well-known lensed broad absorption line (BAL) quasar at z=3.911. The spectroscopic data are taken with the optical DOLoRes and near-IR NICS instruments at TNG, and include the previously unexplored range between CIII] {lambda}1910 and [OIII] {lambda}{lambda}4959,5007. We investigate the possible presence of multiple BALs by computing "balnicity" and absorption indexes (i.e. BI, BI_0_ and AI) for the transitions SiIV {lambda}1400, CIV {lambda}1549, AlIII {lambda}1860 and MgII {lambda}2800. No clear evidence for the presence of absorption features is found in addition to the already known, prominent BAL associated to C IV, which supports a high-ionization BAL classification for APM 08279+5255. We also study the properties of the [OIII], H{beta} and MgII emission lines. We find that [OIII] is intrinsically weak (F_[OIII]_/F_H{beta}_<~0.04), as it is typically found in luminous quasars with a strongly blueshifted CIV emission line (2500km/s for APM 08279+5255). We compute the single-epoch black hole mass based on MgII and H{beta} broad emission lines, finding M_BH_=(2/3)*10^10^{mu}^-1^M_{sun}_, with the magnification factor {mu} that can vary between 4 and 100 according to CO and rest-frame UV-to-mid-IR imaging respectively. Using a MgII equivalent width (EW)-to-Eddington ratio relation, the EW_MgII_~27{AA} measured for APM 08279+5255 translates into an Eddington ratio of ~0.4, which is more consistent with {mu}=4. This magnification factor also provides a value of M_BH_ that is consistent with recent reverberation-mapping measurements derived from CIV and SiIV.
- ID:
- ivo://CDS.VizieR/J/A+A/581/A126
- Title:
- Application of the D^3^PO algorithm
- Short Name:
- J/A+A/581/A126
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze the 6.5yr all-sky data from the Fermi LAT restricted to gamma-ray photons with energies between 0.6-307.2GeV. We present a non-parametric reconstruction of the diffuse photon flux up to several hundred GeV, its all-sky spectral index map, and its angular power spectrum. We decompose the diffuse emission into a cloud-like abd a bubble-like component and analyze their spectra. Additionally, we wrote up a catalog of source candidates that includes 3106 sources. For each source we report the location in the sky, flux, spectral index, and possible associations with sources from the second and third Fermi source catalog.
- ID:
- ivo://CDS.VizieR/J/A+A/559/A10
- Title:
- Arp 102B spectral optical monitoring
- Short Name:
- J/A+A/559/A10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of long-term (1987-2010) optical spectral monitoring of the broad-line radio galaxy Arp 102B, a prototype of an active galactic nucleus with double-peaked broad emission lines that are commonly assumed to be emitted from an accretion disk. To explore the structure of the broad-line region (BLR), we analyze the light-curves of the broad H{alpha} and H{beta} lines and the continuum flux. We aim to estimate the dimensions of the broad-line emitting regions and the mass of the central black hole. We used the cross correlation function to find lags between the lines and continuum variations. We investigated the correlation between line and continuum fluxes in more detail, and explored periodical variations of the red-to-blue line flux ratio using Lomb-Scargle periodograms.
- ID:
- ivo://CDS.VizieR/J/ApJS/148/275
- Title:
- ASCA AGN optical identifications
- Short Name:
- J/ApJS/148/275
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of optical spectroscopic identifications of a bright subsample of 2-10keV hard X-ray-selected sources from the ASCA Medium Sensitivity Survey in the northern sky (AMSSn). The flux limit of the subsample is 3x10^-13^erg/s/cm^2^ in the 2-10keV band. All but one of the 87 hard X-ray-selected sources are optically identified, with AGNs (including broad-line AGNs, narrow-line AGNs, and three BL Lac objects), seven clusters of galaxies, and one galactic star. It is the largest complete sample of hard X-ray-selected AGNs at the bright flux limit. Amounts of absorption to their nuclei are estimated to be hydrogen column densities (NH) of up to 3x10^23^cm^-2^ from their X-ray spectra. Optical properties of X-ray absorbed AGNs with N_H_>1x10^22^cm^-2^ indicate the effects of dust absorption: at redshifts z<0.6, AGNs without broad H{beta} emission lines have significantly larger NH-values than AGNs with broad H{beta} emission lines. At z>0.6, the X-ray absorbed AGNs have a large hard X-ray to optical flux ratio (logf_2-10keV_/f_R_>+1). However, three X-ray absorbed z>0.6 AGNs show strong broad lines. In combination with hard X-ray-selected AGN samples from the ASCA Large Sky Survey, the ASCA Deep Survey in the Lockman Hole, and Chandra Deep Field North, the luminosity distributions of absorbed (N_H_>1x10^22^cm^-2^) and less-absorbed (N_H_<1x10^22^cm^-2^) AGNs are compared.
- ID:
- ivo://CDS.VizieR/J/PASJ/53/445
- Title:
- ASCA Deep survey in Lockman Hole Field
- Short Name:
- J/PASJ/53/445
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of deep observations of the Lockman Hole field with the ASCA SIS, covering 926arcmin^2^ in the 1-7keV energy range, with a sensitivity 3-5 times deeper than the previous ASCA larger area surveys. Utilizing the results of the ROSAT Ultra Deep survey, we have detected 32, 25, and 15 sources in the 1-7, 1-2, and 2-7keV bands, and only 4, 4, and 1 sources remain unidentified, respectively. The average hardness of the sources detected in the 1-7keV band with fluxes of between 10^-14^ and 10^-13^erg/cm^2^/s corresponds to a photon index of 1.65+/-0.10. Type-2 AGNs show significantly harder spectra than type-1s, which can be explained by absorption column densities of N_H_~10^22-23^cm^-2 at the source redshifts. Fifteen sources are detected in the hard-band (2-7keV), consisting of six type-1 AGNs, six type-2 AGNs, one star, one cluster of galaxies, and one unidentified source. Type-2 AGNs make up a major part of hard X-ray populations in the 2-7keV band at a flux level of 3x10^-14^erg/cm^2^/s (2-7 keV). The redshift distributions of type-1 and type-2 AGNs suggest a lack of high luminosity (optically-defined) type-2 AGNs with intrinsic N_H_<10^23^cm^-2, n the redshift range z~1-2 and/or with intrinsic luminosities larger than 3x10^44^erg/s (2-10keV at source frame).
