- ID:
- ivo://CDS.VizieR/J/ApJ/789/135
- Title:
- Gamma-ray bright blazars spectrophotometry
- Short Name:
- J/ApJ/789/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present {gamma}-ray, X-ray, ultraviolet, optical, and near-infrared light curves of 33 {gamma}-ray bright blazars over 4 years that we have been monitoring since 2008 August with multiple optical, ground-based telescopes and the Swift satellite, and augmented by data from the Fermi Gamma-ray Space Telescope and other publicly available data from Swift. The sample consists of 21 flat-spectrum radio quasars (FSRQs) and 12 BL Lac objects (BL Lacs). We identify quiescent and active states of the sources based on their {gamma}-ray behavior. We derive {gamma}-ray, X-ray, and optical spectral indices, {alpha}_{gamma}_, {alpha}_X_, and {alpha}_o_, respectively (F_{nu}_{prop.to}{nu}^{alpha}^), and construct spectral energy distributions during quiescent and active states. We analyze the relationships between different spectral indices, blazar classes, and activity states. We find (1) significantly steeper {gamma}-ray spectra of FSRQs than for BL Lacs during quiescent states, but a flattening of the spectra for FSRQs during active states while the BL Lacs show no significant change; (2) a small difference of {alpha}_X_ within each class between states, with BL Lac X-ray spectra significantly steeper than in FSRQs; (3) a highly peaked distribution of X-ray spectral slopes of FSRQs at ~ -0.60, but a very broad distribution of {alpha}_X_of BL Lacs during active states; (4) flattening of the optical spectra of FSRQs during quiescent states, but no statistically significant change of {alpha}_o_ of BL Lacs between states; and (5) a positive correlation between optical and {gamma}-ray spectral slopes of BL Lacs, with similar values of the slopes. We discuss the findings with respect to the relative prominence of different components of high-energy and optical emission as the flux state changes.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/813/51
- Title:
- {gamma}-ray to IR study of the blazar CTA 102
- Short Name:
- J/ApJ/813/51
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform a multi-wavelength polarimetric study of the quasar CTA 102 during an extraordinarily bright {gamma}-ray outburst detected by the Fermi Large Area Telescope in 2012 September-October when the source reached a flux of F_>100MeV_=5.2+/-0.4x10^-6^photons/cm2/s. At the same time, the source displayed an unprecedented optical and near-infrared (near-IR) outburst. We study the evolution of the parsec-scale jet with ultra-high angular resolution through a sequence of 80 total and polarized intensity Very Long Baseline Array images at 43GHz, covering the observing period from 2007 June to 2014 June. We find that the {gamma}-ray outburst is coincident with flares at all the other frequencies and is related to the passage of a new superluminal knot through the radio core. The powerful {gamma}-ray emission is associated with a change in direction of the jet, which became oriented more closely to our line of sight ({theta}~1.2{deg}) during the ejection of the knot and the {gamma}-ray outburst. During the flare, the optical polarized emission displays intra-day variability and a clear clockwise rotation of electric vector position angles (EVPAs), which we associate with the path followed by the knot as it moves along helical magnetic field lines, although a random walk of the EVPA caused by a turbulent magnetic field cannot be ruled out. We locate the {gamma}-ray outburst a short distance downstream of the radio core, parsecs from the black hole. This suggests that synchrotron self-Compton scattering of NIR to ultraviolet photons is the probable mechanism for the {gamma}-ray production.
- ID:
- ivo://CDS.VizieR/J/MNRAS/336/879
- Title:
- G and K dwarfs UBV(RI)c and ubvy photometry
- Short Name:
- J/MNRAS/336/879
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- K dwarfs have lifetimes older than the present age of the Galactic disc, and are thus ideal stars for investigating the chemical evolution of the disc. We have developed several photometric metallicity indicators for K dwarfs, based on a sample of accurate spectroscopic metallicities for 34 disc and halo G and K dwarfs. The photometric metallicities lead us to develop a metallicity index for K dwarfs based only on their position in the colour-absolute-magnitude diagram. Metallicities have been determined for 431 single K dwarfs drawn from the Hipparcos catalogue, selecting the stars by absolute magnitude and removing multiple systems. The sample is essentially a complete reckoning of the metal content in nearby K dwarfs. We use stellar isochrones to mark the stars by mass, and select a subset of 220 of the stars, which is complete within a narrow mass interval. We fit the data with a model of the chemical evolution of the solar cylinder. We find that only a modest cosmic scatter is required to fit our age-metallicity relation. The model assumes two main infall episodes for the formation of the halo-thick disc and thin disc, respectively. The new data confirm that the solar neighbourhood formed on a long time-scale of the order of 7Gyr.
- ID:
- ivo://CDS.VizieR/J/A+A/520/A109
- Title:
- Gas kinematics of spiral galaxies
- Short Name:
- J/A+A/520/A109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We trace the interaction processes of galaxies at intermediate redshift by measuring the irregularity of their ionized gas kinematics, and investigate these irregularities as a function of the environment (cluster versus field) and of morphological type (spiral versus irregular). We obtain the gas velocity fields by placing three parallel and adjacent VLT/FORS2 slits on each galaxy. To quantify irregularities in the gas kinematics, we use three indicators: the standard deviation of the kinematic position angle ({sigma}_PA_), the mean deviation of the line of sight velocity profile from the cosine form which is measured using high order Fourier terms (k_3,5_/k_1_) and the average misalignment between the kinematical and photometric major axes ({Delta}{phi}). These indicators are then examined together with some photometric and structural parameters (measured from HST and FORS2 images in the optical) such as the disk scale length, rest-frame colors, asymmetry, concentration, Gini coefficient and M20 . Our sample consists of 92 distant galaxies. 16 cluster (z~0.3 and z~0.5) and 29 field galaxies (0.10<=z<=0.91, mean z=0.44) of these have velocity fields with sufficient signal to be analyzed. To compare our sample with the local universe, we also analyze a sample from the SINGS survey.
- ID:
- ivo://CDS.VizieR/VI/102
- Title:
- Geneva stellar evolution tracks and isochrones
- Short Name:
- VI/102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This database was created from an updated version of the empirically and semi-empirically calibrated BaSeL library of synthetic stellar spectra of Lejeune et al. (1997, Cat. <J/A+AS/125/229>, 1998, Cat. <J/A+AS/130/65>) and Westera et al. (1999, ASP Conference Series 192, 203-206) to calculate synthetic photometry in the (UBV)_J_(RI)_C_ JHKLL'M, HST-WFPC2, Geneva, and Washington systems for the entire set of non-rotating Geneva stellar evolution models covering masses from 0.4-0.8 to 120-150M_{sun}_ and metallicities Z=0.0004 (1/50Z_{sun}_) to 0.1 (5Z_{sun}_). The results are provided in a database which includes all individual stellar tracks and the corresponding isochrones covering ages from 10^3^yr to 16-20Gyr in time steps of {Delta}logt=0.05dex. The database also includes a new grid of stellar tracks of very metal-poor stars (Z=0.0004) from 0.8-150M_{sun}_ calculated with the Geneva stellar evolution code. The complete stellar grids are tabulated in the files table1.dat (summary), evol.dat (evolutionary models), and in the files ubv.dat, hst.dat, gen.dat and cmt.dat (synthetic colors in the different photometric systems). These grids are also available as mod* files in subdirectories evol, ubv, hst, gen and cmt. The isochrones for the different photometric systems are summarized in the file table2.dat; the parameters of the isochrones are tabulated in the file iso.dat, the detailed isochrones being available as files iso* in the subdirectories ubv, hst, gen and cmt.
646. GJ 625 HARPS-N data
- ID:
- ivo://CDS.VizieR/J/A+A/605/A92
- Title:
- GJ 625 HARPS-N data
- Short Name:
- J/A+A/605/A92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of a super-Earth orbiting at the inner edge of the habitable zone of the star GJ 625 based on the analysis of the radial-velocity (RV) time series from the HARPS-N spectrograph, consisting in 151 HARPS-N measurements taken over 3.5yr. GJ 625 b is a planet with a minimum mass Msini of 2.82+/-0.51 M_Earth_ with an orbital period of 14.628+/-0.013 days at a distance of 0.078AU of its parent star. The host star is the quiet M2 V star GJ 625, located at 6.5pc from the Sun. We find the presence of a second radial velocity signal in the range 74-85 days that we relate to stellar rotation after analysing the time series of CaII H&K and H{alpha} spectroscopic indicators, the variations of the FWHM of the CCF and and the APT2 photometric light curves. We find no evidence linking the short period radial velocity signal to any activity proxy.
647. GLADE catalog
- ID:
- ivo://CDS.VizieR/VII/275
- Title:
- GLADE catalog
- Short Name:
- VII/275
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We are introducing a value-added full-sky galaxy catalog with high completeness for identifying gravitational wave (GW) sources in order to support future electromagnetic (EM) follow-up projects of the LIGO/Virgo Collaboration. The catalog GLADE (Galaxy List for the Advanced Detector Era) has been constructed (combined and matched) from four existing galaxy catalogs: GWGC, 2MPZ, 2MASS XSC and HyperLEDA. It contains 1918147 galaxies, which is two orders of magnitude greater than the number of galaxies in the GWGC catalog alone (53312), which is currently in use by the collaboration. Furthermore we considered it as a crucial requirement towards the catalog to contain B-band magnitudes and distances for all entries. Therefore we have associated these properties for 548876 2MASS galaxies which lacked them with a regression algorithm teached on a subsample of the 2MPZ catalog. Our catalog is complete to 73Mpc and even at 300Mpc has a relatively high completeness (53%). Naturally, our catalog could be used in a broad range of various astrophysical projects besides EM follow-up efforts.We are introducing a value-added full-sky galaxy catalog with high completeness for identifying gravitational wave (GW) sources in order to support future electromagnetic (EM) follow-up projects of the LIGO/Virgo Collaboration. The catalog has been constructed (combined and matched) from four existing galaxy catalogs: GWGC, 2MPZ, 2MASS XSC and HyperLEDA. It contains 1918147 galaxies, which is two orders of magnitude greater than the number of galaxies in the GWGC catalog alone (53312), which is currently in use by the collaboration. Furthermore we considered it as a crucial requirement towards the catalog to contain B-band magnitudes and distances for all entries. Therefore we have associated these properties for 548,876 2MASS galaxies which lacked them with a regression algorithm teached on a subsample of the 2MPZ catalog. Our catalog is complete to 73 Mpc and even at 300 Mpc has a relatively high completeness (53%). Naturally, our catalog could be used in a broad range of various astrophysical projects besides EM follow-up efforts. For a brief overview of the GLADE project, check out the talk slides (http://aquarius.elte.hu/glade/GLADE_GDalya_LVC2015September.pdf) presented at the 2015 September LIGO-Virgo Collaboration Meeting in Budapest, Hungary. If you have any questions or suggestions about the catalog, please send us an email: dalyag@caesar.elte.hu
648. GLADE v2.3 catalog
- ID:
- ivo://CDS.VizieR/VII/281
- Title:
- GLADE v2.3 catalog
- Short Name:
- VII/281
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We introduce a value-added full-sky catalogue of galaxies, named as Galaxy List for the Advanced Detector Era, or GLADE. The purpose of this catalogue is to (i) help identifications of host candidates for gravitational-wave events, (ii) support target selections for electromagnetic follow-up observations of gravitational-wave candidates, (iii) provide input data on the matter distribution of the local Universe for astrophysical or cosmological simulations, and (iv) help identifications of host candidates for poorly localized electromagnetic transients, such as gamma-ray bursts observed with the InterPlanetary Network. Both being potential hosts of astrophysical sources of gravitational waves, GLADE includes inactive and active galaxies as well. GLADE was constructed by cross-matching and combining data from five separate (but not independent) astronomical catalogues: GWGC, 2MPZ, 2MASS XSC, HyperLEDA, and SDSS-DR12Q. GLADE is complete up to d_L_=37^+3^_-4_Mpc in terms of the cumulative B-band luminosity of galaxies within luminosity distance dL, and contains all of the brightest galaxies giving half of the total B-band luminosity up to d_L_=91Mpc. As B-band luminosity is expected to be a tracer of binary neutron star mergers (currently the prime targets of joint GW+EM detections), our completeness measures can be used as estimations of completeness for containing all binary neutron star merger hosts in the local Universe.
- ID:
- ivo://CDS.VizieR/J/AJ/148/32
- Title:
- Globular cluster candidates in NGC 3115
- Short Name:
- J/AJ/148/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Hubble Space Telescope/Advanced Camera for Surveys (HST/ACS) g and z photometry and half-light radii R_h_ measurements of 360 globular cluster (GC) candidates around the nearby S0 galaxy NGC 3115. We also include Subaru/Suprime-Cam g, r, and i photometry of 421 additional candidates. The well-established color bimodality of the GC system is obvious in the HST/ACS photometry. We find evidence for a "blue tilt" in the blue GC subpopulation, wherein the GCs in the blue subpopulation get redder as luminosity increases, indicative of a mass-metallicity relationship. We find a color gradient in both the red and blue subpopulations, with each group of clusters becoming bluer at larger distances from NGC 3115. The gradient is of similar strength in both subpopulations, but is monotonic and more significant for the blue clusters. On average, the blue clusters have ~10% larger R_h_than the red clusters. This average difference is less than is typically observed for early-type galaxies but does match that measured in the literature for the Sombrero Galaxy (M104), suggesting that morphology and inclination may affect the measured size difference between the red and blue clusters. However, the scatter on the R_h_ measurements is large. We also identify 31 clusters more extended than typical GCs, which we term ultra-compact dwarf (UCD) candidates. Many of these objects are actually considerably fainter than typical UCDs. While it is likely that a significant number will be background contaminants, six of these UCD candidates are spectroscopically confirmed as NGC 3115 members. To explore the prevalence of low-mass X-ray binaries in the GC system, we match our ACS and Suprime-Cam detections to corresponding Chandra X-ray sources. We identify 45 X-ray-GC matches: 16 among the blue subpopulation and 29 among the red subpopulation. These X-ray/GC coincidence fractions are larger than is typical for most GC systems, probably due to the increased depth of the X-ray data compared to previous studies of GC systems.
- ID:
- ivo://CDS.VizieR/J/ApJ/835/184
- Title:
- Globular cluster candidates in NGC4258
- Short Name:
- J/ApJ/835/184
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to explore the relationship between globular cluster total number, N_GC_, and central black hole mass, M_*_, in spiral galaxies, and compare it with that recently reported for ellipticals. We present results for the Sbc galaxy NGC 4258, from Canada-France-Hawaii Telescope data. Thanks to water masers with Keplerian rotation in a circumnuclear disk, NGC 4258 has the most precisely measured extragalactic distance and supermassive black hole mass to date. The globular cluster (GC) candidate selection is based on the (u*-i') versus (i'-Ks) diagram, which is a superb tool to distinguish GCs from foreground stars, background galaxies, and young stellar clusters, and hence can provide the best number counts of GCs from photometry alone, virtually free of contamination, even if the Galaxy is not completely edge-on. The mean optical and optical-near-infrared colors of the clusters are consistent with those of the Milky Way and M 31, after extinction is taken into account. We directly identify 39 GC candidates; after completeness correction, GC luminosity function extrapolation, and correction for spatial coverage, we calculate a total N_GC_=144+/-31_-36_^+38^ (random and systematic uncertainties, respectively). We have thus increased to six the sample of spiral galaxies with measurements of both M_*_ and N_GC_. NGC 4258 has a specific frequency S_N_=0.4+/-0.1 (random uncertainty), and is consistent within 2{sigma} with the N_GC_ versus M_*_ correlation followed by elliptical galaxies. The Milky Way continues to be the only spiral that deviates significantly from the relation.
