- ID:
- ivo://CDS.VizieR/J/MNRAS/366/645
- Title:
- LARCS. 11 X-ray luminous clusters
- Short Name:
- J/MNRAS/366/645
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of the spectroscopic and photometric catalogues of 11 X-ray luminous clusters at 0.07<z<0.16 from the Las Campanas/Anglo-Australian Telescope Rich Cluster Survey. Our spectroscopic data set consists of over 1600 galaxy cluster members, of which two-thirds are outside r_200_. These spectra allow us to assign cluster membership using a detailed mass model and expand on our previous work on the cluster colourmagnitude relation (CMR) where membership was inferred statistically.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/357/1357
- Title:
- Large-scale clumpy structure in Lynx region
- Short Name:
- J/MNRAS/357/1357
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of a probable large-scale structure composed of many galaxy clumps around the known twin clusters at z=1.26 and 1.27 in the Lynx region. Our analysis is based on deep, panoramic, and multicolour imaging, 26.4x24.1arcmin^2^ in VRi'z' bands with the Suprime-Cam on the 8.2-m Subaru telescope. This unique, deep and wide-field imaging data set allows us for the first time to map out the galaxy distribution in the highest-redshift supercluster known.
- ID:
- ivo://CDS.VizieR/J/ApJS/247/71
- Title:
- Large-scale environment of radio galaxies. II.
- Short Name:
- J/ApJS/247/71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In our previous analysis we investigated the large-scale environment of two samples of radio galaxies (RGs) in the local universe (i.e., with redshifts z_src_<=0.15), classified as FR I and FR II on the basis of their radio morphology. The analysis was carried out using (i) extremely homogeneous catalogs and (ii) a new method, known as cosmological overdensity, to investigate their large-scale environments. We concluded that, independently of the shape of their radio extended structure, RGs inhabit galaxy-rich large-scale environments with similar characteristics and richness. In the present work, we first highlight additional advantages of our procedure, which does not suffer cosmological biases and/or artifacts, and then we carry out an additional statistical test to strengthen our previous results. We also investigate properties of RG environments using those of the cosmological neighbors. We find that large-scale environments of both FR Is and FR IIs are remarkably similar and independent of the properties of central RG. Finally, we highlight the importance of comparing radio sources in the same redshift bins to obtain a complete overview of their large-scale environments.
- ID:
- ivo://CDS.VizieR/J/ApJ/681/1163
- Title:
- Late-type galaxies in Chandra deep fields
- Short Name:
- J/ApJ/681/1163
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the X-ray evolution over the last ~9Gyr of cosmic history (i.e., since z=1.4) of late-type galaxy populations in the Chandra Deep Field-North and Extended Chandra Deep Field-South (CDF-N and E-CDF-S, respectively; jointly CDFs) survey fields. Our late-type galaxy sample consists of 2568 galaxies, which were identified using rest-frame optical colors and HST morphologies. We utilized X-ray stacking analyses to investigate the X-ray emission from these galaxies, emphasizing the contributions from normal galaxies that are not dominated by active galactic nuclei (AGNs). Over this redshift range, we find significant increases (factors of ~5-10) in the X-ray-to-optical mean luminosity ratio (L_X_/L_B_) and the X-ray-to-stellar mass mean ratio (L_X_/M_*_) for galaxy populations selected by L_B_ and M_*_, respectively. When analyzing galaxy samples selected via SFR, we find that the mean X-ray-to-SFR ratio (L_X_/SFR) is consistent with being constant over the entire redshift range for galaxies with SFR=1-100M_{sun}_/yr, thus demonstrating that X-ray emission can be used as a robust indicator of star formation activity out to z~1.4. We find that the star formation activity (as traced by X-ray luminosity) per unit stellar mass in a given redshift bin increases with decreasing stellar mass over the redshift range z=0.2-1, which is consistent with previous studies of how star formation activity depends on stellar mass. Finally, we extend our X-ray analyses to Lyman break galaxies at z~3 and estimate that L_X_/L_B_ at z~3 is similar to its value at z=1.4.
- ID:
- ivo://CDS.VizieR/J/ApJ/348/253
- Title:
- Late type giants and supergiants in X-Ray
- Short Name:
- J/ApJ/348/253
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results are presented of an extensive X-ray survey of 380 giant and supergiant stars of spectral types from F to M, carried out with the Einstein Observatory. It was found that the observed F giants or subgiants (slightly evolved stars with a mass M less than about 2 solar masses) are X-ray emitters at the same level of main-sequence stars of similar spectral type. The G giants show a range of emission more than 3 orders of magnitude wide; some single G giants exist with X-ray luminosities comparable to RS CVn systems, while some nearby large G giants have upper limits on the X-ray emission below typical solar values. The K giants have an observed X-ray emission level significantly lower than F and F giants. None of the 29 M giants were detected, except for one spectroscopic binary.
- ID:
- ivo://CDS.VizieR/J/ApJ/833/159
- Title:
- Late X-ray emission of binary-driven hypernovae
- Short Name:
- J/ApJ/833/159
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It has previously been discovered that there is a universal power-law behavior exhibited by the late X-ray emission (LXRE) of a "golden sample" of six long energetic GRBs, when observed in the rest frame of the source. This remarkable feature, independent of the different isotropic energy (E_iso_) of each GRB, has been used to estimate the cosmological redshift of some long GRBs. This analysis is extended here to a new class of 161 long GRBs, all with E_iso_>10^52^erg. These GRBs are indicated as binary-driven hypernovae (BdHNe) in view of their progenitors: a tight binary system composed of a carbon-oxygen core (CO_core_) and a neutron star undergoing an induced gravitational collapse (IGC) to a black hole triggered by the CO_core_ explosion as a supernova (SN).
- ID:
- ivo://CDS.VizieR/J/MNRAS/406/1318
- Title:
- Lensed-arc statistics of galaxy clusters
- Short Name:
- J/MNRAS/406/1318
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The statistics of strongly lensed arcs in samples of galaxy clusters provide information on cluster structure that is complementary to that from individual clusters. However, samples of clusters that have been analysed to date have been either small, heterogeneous or observed with limited angular resolution. We measure the lensed-arc statistics of 97 clusters imaged at high angular resolution with the Hubble Space Telescope, identifying lensed arcs using two automated arc-detection algorithms. The sample includes similar numbers of X-ray-selected [MAssive Cluster Survey (MACS)] and optically selected [Red-Sequence Cluster Survey (RCS)] clusters, and spans cluster redshifts in the range 0.2<z<1. We compile a catalogue of 42 arcs in the X-ray-selected subsample and seven arcs in the optical subsample. All but five of these arcs are reported here for the first time.
- ID:
- ivo://CDS.VizieR/J/ApJ/854/107
- Title:
- Light curves of 2 Seyfert 1 galaxies
- Short Name:
- J/ApJ/854/107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical continuum lags for two Seyfert 1 galaxies, MCG+08-11-011 and NGC 2617, using monitoring data from a reverberation mapping campaign carried out in 2014. Our light curves span the ugriz filters over four months, with median cadences of 1.0 and 0.6 days for MCG+08-11-011 and NGC 2617, respectively, combined with roughly daily X-ray and near-UV data from Swift for NGC 2617. We find lags consistent with geometrically thin accretion-disk models that predict a lag-wavelength relation of {tau}{propto}{lambda}^4/3^. However, the observed lags are larger than predictions based on standard thin-disk theory by factors of 3.3 for MCG+08-11-011 and 2.3 for NGC 2617. These differences can be explained if the mass accretion rates are larger than inferred from the optical luminosity by a factor of 4.3 in MCG+08-11-011 and a factor of 1.3 in NGC 2617, although uncertainty in the SMBH masses determines the significance of this result. While the X-ray variability in NGC 2617 precedes the UV/optical variability, the long (2.6 day) lag is problematic for coronal reprocessing models.
- ID:
- ivo://CDS.VizieR/J/ApJS/219/18
- Title:
- LIRAS: LoCuSS IR AGN survey
- Short Name:
- J/ApJS/219/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 290 24{mu}m-selected active galactic nuclei (AGNs) mostly at z~0.3-2.5, within 5.2{deg}^2^ distributed as 25'x25' fields around each of 30 galaxy clusters in the Local Cluster Substructure Survey. The sample is nearly complete to 1mJy at 24{mu}m, and has a rich multiwavelength set of ancillary data; 162 are detected by Herschel. We use spectral templates for AGNs, stellar populations, and infrared (IR) emission by star-forming galaxies to decompose the spectral energy distributions (SEDs) of these AGNs and their host galaxies, and estimate their star formation rates, AGN luminosities, and host galaxy stellar masses. The set of templates is relatively simple: a standard Type-1 quasar template; another for the photospheric output of the stellar population; and a far-infrared star-forming template. For the Type-2 AGN SEDs, we substitute templates including internal obscuration, and some Type-1 objects require a warm component (T>~50K). The individually Herschel-detected Type-1 AGNs and a subset of 17 Type-2 AGNs typically have luminosities >10^45^erg/s, and supermassive black holes of ~3x10^8^M_{sun}_ emitting at ~10% of the Eddington rate. We find them in about twice the numbers of AGNs identified in SDSS data in the same fields, i.e., they represent typical high-luminosity AGNs, not an IR-selected minority. These AGNs and their host galaxies are studied further in an accompanying paper.
- ID:
- ivo://CDS.VizieR/J/A+A/344/521
- Title:
- LMC variable X-ray sources
- Short Name:
- J/A+A/344/521
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ROSAT PSPC (Cat. <IX/11>) performed more than 200 pointed observations of the Large Magellanic Cloud (LMC) between 1990 and 1994. Most of the LMC was covered more than once and a large fraction at least ten times, making the PSPC observations an in valuable archive to study long-term time variability in the LMC. We performed a systematic search for variable X-ray sources in the LMC and found 27 sources which showed flux variations by factors between 3 and more than 1000. A comparison of the temporal and spectral characteristics of 15 X-ray sources which are not yet identified optically with those of the previously known sources in our sample allows to draw first conclusions about their nature. Up to six of the unidentified sources are promising candidates for high mass X-ray binaries in the LMC. Six sources are probably foreground stars, two soft objects might be supersoft sources and one source could be a black hole candidate. Most of the X-ray binary candidates are found in the area of the LMC 4 supergiant shell leading to a significant concentration of such systems in that region, consistent with the idea of being born in the stellar formation event which created the shell.