- ID:
- ivo://CDS.VizieR/J/A+A/610/A14
- Title:
- ASASSN-15lh MUSE host spectroscopy
- Short Name:
- J/A+A/610/A14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The progenitors of astronomical transients are linked to a specific stellar population and galactic environment, and observing their host galaxies hence constrains the physical nature of the transient itself. Here, we use imaging from the Hubble Space Telescope, and spatially resolved, medium-resolution spectroscopy from the Very Large Telescope obtained with X-shooter and MUSE to study the host of the very luminous transient ASASSN-15lh. The dominant stellar population at the transient site is old (around 1 to 2Gyr) without signs of recent star formation. We also detect emission from ionized gas, originating from three different, time invariable, narrow components of collisionally excited metal and Balmer lines. The ratios of emission lines in the Baldwin-Phillips-Terlevich diagnostic diagram indicate that the ionization source is a weak active galactic nucleus with a black hole mass of M_BH_=5_-3_^+8^x10^8^M_{sun}_, derived through the M*-{sigma} relation. The narrow line components show spatial and velocity offsets on scales of 1kpc and 500km/s, respectively; these offsets are best explained by gas kinematics in the narrow-line region. The location of the central component, which we argue is also the position of the supermassive black hole, aligns with that of the transient within an uncertainty of 170pc. Using this positional coincidence as well as other similarities with the hosts of tidal disruption events, we strengthen the argument that the transient emission observed as ASASSN-15lh is related to the disruption of a star around a supermassive black hole, most probably spinning with a Kerr parameter a_BH_>=0.5.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/463/3813
- Title:
- ASASSN-15oi UBVI M2W1W2 light curves
- Short Name:
- J/MNRAS/463/3813
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present ground-based and Swift photometric and spectroscopic observations of the tidal disruption event (TDE) ASASSN-15oi, discovered at the centre of 2MASX J20390918-3045201 (d~=216Mpc) by the All-Sky Automated Survey for SuperNovae. The source peaked at a bolometric luminosity of L~=1.3x10^44^erg/s and radiated a total energy of E~=6.6x10^50^ erg over the first ~3.5 months of observations. The early optical/UV emission of the source can be fit by a blackbody with temperature increasing from T~=2x10^4^K to T~=4x10^4^K while the luminosity declines from L~=1.3x10^44^erg/s to L~=2.3x10^43^erg/s, requiring the photosphere to be shrinking rapidly. The optical/UV luminosity decline during this period is most consistent with an exponential decline, L{prop.to}e^-(t-t_0)/tau_^, with {tau}~=46.5d for t_0_~=57241.6 (MJD), while a power-law decline of L{prop.to}(t-t_0_)^-{alpha}^ with t_0_~=57212.3 and {alpha}=1.62 provides a moderately worse fit. ASASSN-15oi also exhibits roughly constant soft X-ray emission that is significantly weaker than the optical/UV emission. Spectra of the source show broad helium emission lines and strong blue continuum emission in early epochs, although these features fade rapidly and are not present ~3 months after discovery. The early spectroscopic features and colour evolution of ASASSN-15oi are consistent with a TDE, but the rapid spectral evolution is unique among optically selected TDEs.
- ID:
- ivo://CDS.VizieR/J/AcA/59/33
- Title:
- ASAS. Variable stars catalog in Kepler field.
- Short Name:
- J/AcA/59/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog is a result of the analysis of VI photometry obtained during the first 17-month observations in the ASAS3-North station. The variable stars we present are divided into eleven groups according to the presented variability; the groups are briefly discussed. The catalog is intended to be a source of information for target selection process and follow-up programs.
- ID:
- ivo://CDS.VizieR/II/264
- Title:
- ASAS Variable Stars in Southern hemisphere
- Short Name:
- II/264
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the photometric data from the 9x9deg^2^ ASAS camera monitoring the whole southern hemisphere in V-band. Light curves have been classified using the automated algorithm taking into account periods, amplitudes, Fourier coefficients of the light curves, 2MASS colors and IRAS infrared fluxes. Basic photometric properties are presented in the tables and some examples of thumbnail light curves are printed for reference. All photometric data are available over the INTERNET at http://www.astrouw.edu.pl/~gp/asas/asas.html or http://bulge3.astro.Princeton.EDU/~asas/ .
- 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).
- ID:
- ivo://CDS.VizieR/J/ApJS/134/77
- Title:
- ASCA Galactic Plane Survey faint X-ray sources
- Short Name:
- J/ApJS/134/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The X-ray emission from the central region of the Galactic plane, |l|<~45{deg} and |b|<~0.4{deg}, was studied in the 0.710keV energy band with a spatial resolution of ~3' with the Advanced Satellite for Cosmology and Astrophysics (ASCA) observatory. We developed a new analysis method for the ASCA data to resolve discrete sources from the extended Galactic ridge X-ray emission (GRXE). We successfully resolved 163 discrete sources with an X-ray flux down to 10^-12.5^ergs/cm^2^/s and determined the intensity variations of the GRXE as a function of the Galactic longitude with a spatial resolution of about 1{deg}.
1128. ASCA Large Sky Survey
- ID:
- ivo://CDS.VizieR/J/ApJ/518/656
- Title:
- ASCA Large Sky Survey
- Short Name:
- J/ApJ/518/656
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carried out the first wide-area unbiased survey with the ASCA satellite in the 0.7-10keV band around a north Galactic-pole region covering a continuous area of 7deg^2^ (Large Sky Survey; LSS). To make the best use of ASCA's capabilities, we developed a new source-detection method in which the complicated detector responses are fully taken into account. Applying this method to the entire LSS data independently in the total (0.7-7keV), hard (2-10keV), and soft (0.7-2keV) bands, we detected 107 sources altogether, with sensitivity limits of 6x10^-14^ (0.7-7keV), 1x10^-13^ (2-10keV), and 2x10^-14^ergs/s/cm^2^ (0.7-2keV), respectively. A complete list of the detected sources is presented.
1129. ASCA sources in the SMC
- ID:
- ivo://CDS.VizieR/J/PASJ/55/161
- Title:
- ASCA sources in the SMC
- Short Name:
- J/PASJ/55/161
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We made 22 observations on the Small Magellanic Cloud (SMC) and covered full regions of the main body and the eastern wing by the end of the ASCA mission. We detected 106 discrete sources with a criterion of S/N>5 and performed systematic analyses on all of the sources. We determined the source positions with an ~40" error radius (90% confidence) for sources detected in the central 20' radius of the GIS. We detected coherent pulsations from 17 sources. Among them, eight were newly discovered during this study. We classified most of these pulsars as X-ray binary pulsars (XBPs) based on their properties, such as the flux variability and the existence of an optical counterpart. We detected X-ray emission from eight supernova remnants (SNRs). Based on these ASCA results and further information from ROSAT, SAX, RXTE, CGRO, Chandra, and XMM-Newton, we compiled comprehensive catalogues of discrete X-ray sources in the Small Magellanic Cloud.
- ID:
- ivo://CDS.VizieR/VI/145
- Title:
- ASC Gaia Attitude Star Catalog
- Short Name:
- VI/145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ASC is a compilation produced for the Gaia mission. We have combined data from the following catalogs or datasets to produce a homogenous list of positions, proper motions, photometry in a blue and red band and estimates of the magnitudes in the Gaia G and G_RVS bands: Tycho2, UCAC4, Hipparcos, PPMXL, GSC2.3 and Sky2000. Originally ASC sources were selected from the Initial Gaia Source List (IGSL, <A HREF="http://cdsarc.u-strasbg.fr/cgi-bin/Cat?I/324">I/324</A>). However, here we produce a cleaner catalog starting from the bright source catalogs and using the following criteria: 1) The candidate must be in the Tycho2, UCAC4, Hipparcos or Sky2000 catalog. 2) The Gaia G magnitude must be brighter than 13.4. 3) The star must be isolated from other objects of similar magnitudes 4) The object must not be in the Washington Double Star catalog 5) If a healpix 6th region has more than 1000 objects the magnitude limit is reduced to reduce the number of objects in that region. Since the ASC was produced independently from the IGSL using different procedures there is not a direct 1 to 1 match between ASC and IGSL entries. We have matched the ASC to the IGSL and found that 9 out of the 8 million entries do not have a clear match. Since there may still remain ambiguous matches in the 8 million matched objects, we decided to assign the sourceIDs of the IGSL with the adjustment that the runningnumber is equal to the IGSL runningnumber + 320000. Included Catalogs: Tycho2, UCAC4, Sky2000, HIPPARCOS for candidates and the PPMXL, GSC2.3 were used to calculating magnitudes.
