- ID:
- ivo://CDS.VizieR/J/A+A/555/A56
- Title:
- T1C photometry of NGC7507
- Short Name:
- J/A+A/555/A56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- There is strong evidence that globular cluster systems (GCSs) of massive galaxies are largely assembled by infall/accretion processes. Therefore, we expect the GCSs of isolated elliptical galaxies to be poor. Although not completely isolated, NGC 7507 is a massive field elliptical galaxy with an apparently very low dark matter content. We determine the richness, the colour distribution, and the structural properties of the GCS of NGC 7507. We performed wide-field Washington photometry with data obtained with the MOSAIC II camera at the 4m-Blanco telescope (CTIO, Chile).
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- ID:
- ivo://CDS.VizieR/J/ApJ/899/136
- Title:
- TESS light curve of AGN NGC 4395
- Short Name:
- J/ApJ/899/136
- Date:
- 03 Dec 2021 13:06:51
- Publisher:
- CDS
- Description:
- We present optical light curves from the Transiting Exoplanet Survey Satellite (TESS) for the archetypical dwarf active galactic nucleus (AGN) in the nearby galaxy NGC 4395 hosting a ~105M{sun} supermassive black hole (SMBH). Significant variability is detected on timescales from weeks to hours before reaching the background noise level. The ~month-long, 30 minute-cadence, high-precision TESS light curve can be well fit by a simple damped random walk (DRW) model, with the damping timescale {tau}DRW constrained to be 2.3_-0.7_^+1.8^days (1{sigma}). NGC 4395 lies almost exactly on the extrapolation of the {tau }_DRW_-M_BH_ relation measured for AGNs with BH masses that are more than three orders of magnitude larger. The optical variability periodogram can be well fit by a broken power law with the high-frequency slope (-1.88{+/-}0.15) and the characteristic timescale ({tau}_br_=1/(2{pi}f_br_)=1.4_-0.5_^+1.9^days) consistent with the DRW model within 1{sigma}. This work demonstrates the power of TESS light curves in identifying low-mass accreting SMBHs with optical variability, and a potential global {tau}_DRW}_-M_BH_ relation that can be used to estimate SMBH masses with optical variability measurements.
- ID:
- ivo://CDS.VizieR/J/A+A/608/A68
- Title:
- TeV/non-TeV BL Lacs multi-lambda fluxes
- Short Name:
- J/A+A/608/A68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have collected the most complete multi-wavelength (6.0-6.0E^-18^cm) dataset of very high energy (VHE) gamma-ray emitting (TeV) BL Lacs, which are the most numerous extragalactic VHE sources. Using significant correlations between different bands, we aim to identify the best TeV BL Lac candidates that can be discovered by the current and next generation of imaging air Cherenkovtelescopes. We formed five datasets from lower energy data, i.e. radio, mid-infrared, optical, X-rays, and GeV gamma-ray, and five VHE gamma-ray datasets to perform a correlation study between different bands and to construct the prediction method. The low energy datasets were averaged for individual sources, while the VHE gamma-ray data were divided into subsets according to the flux state of the source. We then looked for significant correlations and determined their best-fit parameters. Using the best-fit parameters we predicted the level of VHE gamma-ray flux for a sample of 182 BL Lacs, which have not been detected at TeV energies. We identified the most promising TeV BL Lac candidates based on the predicted VHE gamma-ray flux for each source. We found 14 significant correlations between radio, mid-infrared, optical, gamma-ray, and VHE gamma-ray bands. The correlation between optical and VHE gamma-ray luminosity is established for the first time. We attribute this to the more complete sample and more accurate handling of host galaxy flux in our work. We found nine BL Lac candidates whose predicted VHE gamma-ray flux is high enough for detection in less than 25 hours with current imaging air Cherenkov telescopes.
- ID:
- ivo://CDS.VizieR/J/AJ/151/82
- Title:
- The 4 brightest red giants in the UFD galaxy Ret 2
- Short Name:
- J/AJ/151/82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ultra-faint dwarf (UFD) galaxy Reticulum 2 (Ret 2) was recently discovered in images obtained by the Dark Energy Survey (Diehl et al. 2014SPIE.9149E..0VD). We have observed the four brightest red giants in Ret 2 at high spectral resolution using the Michigan/Magellan Fiber System. We present detailed abundances for as many as 20 elements per star, including 12 elements heavier than the Fe group. We confirm previous detection of high levels of r-process material in Ret 2 (mean [Eu/Fe]=+1.69+/-0.05) found in three of these stars (mean [Fe/H]=-2.88+/-0.10). The abundances closely match the r-process pattern found in the well-studied metal-poor halo star CS 22892-052. Such r-process-enhanced stars have not been found in any other UFD galaxy, though their existence has been predicted by at least one model. The fourth star in Ret 2 ([Fe/H]=-3.42+/-0.20) contains only trace amounts of Sr ([Sr/Fe]=-1.73+/-0.43) and no detectable heavier elements. One r-process enhanced star is also enhanced in C (natal [C/Fe]~+1.1). This is only the third such star known, which suggests that the nucleosynthesis sites leading to C and r-process enhancements are decoupled. The r-process-deficient star is enhanced in Mg ([Mg/Fe]=+0.81+/-0.14), and the other three stars show normal levels of {alpha}-enhancement (mean [Mg/Fe]=+0.34+/-0.03). The abundances of other {alpha} and Fe-group elements closely resemble those in UFD galaxies and metal-poor halo stars, suggesting that the nucleosynthesis that led to the large r-process enhancements either produced no light elements or produced light-element abundance signatures indistinguishable from normal supernovae.
- ID:
- ivo://CDS.VizieR/J/AJ/126/197
- Title:
- The Carina projects. I. Bright variables stars
- Short Name:
- J/AJ/126/197
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new BV time series data of the Carina dwarf spheroidal galaxy (dSph). Current data cover an area of ~0.3deg^2^ around the center of the galaxy and allow us to identify 92 variables. Among them 75 are RR Lyrae stars, 15 are bona fide anomalous Cepheids, one might be a Galactic field RR Lyrae star, and one is located along the Carina red giant branch. Expanding upon the seminal photographic investigation by Saha, Monet, & Seitzer (1986AJ.....92..302S) we supply, for the first time, accurate estimates of their pulsation parameters (periods, amplitudes, mean magnitudes, and colors) on the basis of CCD photometry. Approximately 50% of both RR Lyrae stars and anomalous Cepheids are new identifications. Among the RR Lyrae sample, six objects are new candidate double-mode (RRd) variables. On the basis of their pulsation properties we estimate that two variables (V158, V182) are about 50% more massive than typical RR Lyrae stars, while the bulk of the anomalous Cepheids are roughly a factor of 2 more massive than fundamental-mode (RRab) RR Lyrae stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/830/126
- Title:
- The Carina project. X. Radial velocities
- Short Name:
- J/ApJ/830/126
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new radial velocity (RV) measurements of old (horizontal branch) and intermediate-age (red clump) stellar tracers in the Carina dwarf spheroidal. They are based on more than 2200 low-resolution spectra collected with VIMOS at Very Large Telescope (VLT). The targets are faint (20<~V<~21.5mag), but the accuracy at the faintest limit is <=9km/s. These data were complemented with RV measurements either based on spectra collected with FORS2 and FLAMES/GIRAFFE at VLT or available in the literature. We ended up with a sample of 2748 stars and among them, 1389 are candidate Carina stars. We found that the intermediate-age stellar component shows a well-defined rotational pattern around the minor axis. The western and the eastern side of the galaxy differ by +5 and -4km/s when compared with the main RV peak. The old stellar component is characterized by a larger RV dispersion and does not show evidence of the RV pattern. We compared the observed RV distribution with N-body simulations for a former disky dwarf galaxy orbiting a giant Milky Way-like galaxy. We rotated the simulated galaxy by 60{deg} with respect to the major axis, we kept the observer on the orbital plane of the dwarf and extracted a sample of stars similar to the observed one. Observed and predicted V_rot_/{sigma} ratios across the central regions are in remarkable agreement. This evidence indicates that Carina was a disky dwarf galaxy that experienced several strong tidal interactions with the Milky Way. Owing to these interactions, Carina transformed from a disky to a prolate spheroid and the rotational velocity transformed into random motions.
- ID:
- ivo://CDS.VizieR/J/ApJS/197/21
- Title:
- The Carnegie-Irvine Galaxy Survey (CGS). I.
- Short Name:
- J/ApJS/197/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Carnegie-Irvine Galaxy Survey (CGS) is a long-term program to investigate the photometric and spectroscopic properties of a statistically complete sample of 605 bright (B_T_<12.9mag), southern ({delta}<0{deg}) galaxies using the facilities at Las Campanas Observatory. This paper, the first in a series, outlines the scientific motivation of CGS, defines the sample, and describes the technical aspects of the optical broadband (BVRI) imaging component of the survey, including details of the observing program, data reduction procedures, and calibration strategy. The overall quality of the images is quite high, in terms of resolution (median seeing ~1"), field of view (8.9'x8.9'), and depth (median limiting surface brightness ~27.5, 26.9, 26.4, and 25.3mag/arcsec^2^ in the B, V, R, and I bands, respectively). We prepare a digital image atlas showing several different renditions of the data, including three-color composites, star-cleaned images, stacked images to enhance faint features, structure maps to highlight small-scale features, and color index maps suitable for studying the spatial variation of stellar content and dust. In anticipation of upcoming science analyses, we tabulate an extensive set of global properties for the galaxy sample. These include optical isophotal and photometric parameters derived from CGS itself, as well as published information on multiwavelength (ultraviolet, U-band, near-infrared, far-infrared) photometry, internal kinematics (central stellar velocity dispersions, disk rotational velocities), environment (distance to nearest neighbor, tidal parameter, group, or cluster membership), and HI content.
- ID:
- ivo://CDS.VizieR/J/ApJS/243/24
- Title:
- The CASBaH galaxy redshift survey
- Short Name:
- J/ApJS/243/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the survey for galaxies in the fields surrounding nine sightlines to far-UV bright, z~1 quasars that define the COS Absorption Survey of Baryon Harbors (CASBaH) program. The photometry and spectroscopy that comprise the data set come from a mixture of public surveys (SDSS, DECaLS) and our dedicated efforts on private facilities (Keck, MMT, LBT). We report the redshifts and stellar masses for 5902 galaxies within ~10 comoving-Mpc of the sightlines with a median of \bar{z}=0.28 and \bar{M}_*_~10^10.1^M_{sun}_. This data set, publicly available as the CASBaH specDB, forms the basis of several recent and ongoing CASBaH analyses. Here, we perform a clustering analysis of the galaxy sample with itself (auto-correlation) and against the set of O VI absorption systems (cross-correlation) discovered in the CASBaH quasar spectra with column densities N(O^+5^)>=10^13.5^/cm^2^. For each, we describe the measured clustering signal with a power-law correlation function {xi}(r)=(r/r_0_)^-{gamma}^ and find that (r_0_,{gamma})=(5.48+/-0.07h_100_^-1^Mpc,1.33+/-0.04) for the auto-correlation and (6.00_-0.77_^+1.09^h_100_^-1^Mpc,1.25+/-0.18) for galaxy-OVI cross-correlation. We further estimate a bias factor of b_gg_=1.3+/-0.1 from the galaxy-galaxy auto-correlation, indicating the galaxies are hosted by halos with mass M_halo_~10^12.1+/-0.05^M_{sun}_. Finally, we estimate an OVI-galaxy bias factor b_OVI_=1.0+/-0.1 from the cross-correlation which is consistent with OVI absorbers being hosted by dark matter halos with typical mass M_halo_~10^11^M_{sun}_. Future works with upcoming data sets (e.g., CGM2) will improve upon these results and will assess whether any of the detected OVI arises in the intergalactic medium.
- ID:
- ivo://CDS.VizieR/J/A+A/597/A18
- Title:
- The central black hole in NGC 4414
- Short Name:
- J/A+A/597/A18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present our mass estimate of the central black hole in the isolated spiral galaxy NGC 4414. Using natural guide star adaptive optics assisted observations with the Gemini Near-Infrared Integral Field Spectrometer (NIFS) and the natural seeing Gemini Multi-Object Spectrographs-North (GMOS), we derived two-dimensional stellar kinematic maps of NGC 4414 covering the central 1.5-arcsec and 10-arcsec, respectively, at a NIFS spatial resolution of 0.13-arcsec. The kinematic maps reveal a regular rotation pattern and a central velocity dispersion dip down to around 105km/s. We constructed dynamical methods using two different methods: Jeans anisotropic dynamical modeling and axisymmetric Schwarzschild modeling. Both modeling methods give consistent results, but we cannot constrain the lower mass limit and only measure an upper limit for the black hole mass of M_bh_=1.56x10^6^M_{sun}_ (at 3{sigma{ level) which is at least 1{sigma} below the recent Mbh-sigma_e relations. Further tests with dark matter, mass-to-light ratio variation and different light models confirm that our results are not dominated by uncertainties. The derived upper limit mass is not only below the Mbh-sigma_e relation, but is also five times lower than the lower limit black hole mass anticipated from the resolution limit of the sphere of influence. This proves that via high quality integral field data we are now able to push black hole measurements down to at least five times less than the resolution limit.
880. The CfA2S catalog
- ID:
- ivo://CDS.VizieR/J/ApJS/121/287
- Title:
- The CfA2S catalog
- Short Name:
- J/ApJS/121/287
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present redshifts for a sample of 4391 galaxies with magnitude m_B(0)_<=15.5 covering 20h<=RA<=4h in right ascension and -2.5{deg}<=DE<=90{deg} in declination. This sample is complete for all galaxies in the merge of the Zwicky et al. and Nilson catalogs in the south Galactic cap. Redshifts for 2964 of these were measured as part of the second CfA Redshift Survey. The data reveal large voids in the foreground and background of the Perseus-Pisces Supercluster. The largest of these voids lies at a mean velocity ~8000km/s, has diameter ~5000km/s, and is enclosed by a complex of dense structures. The large structure known as the Perseus-Pisces Supercluster forms the near side of this complex. On the far side of this large void, at a mean velocity ~12000km/s, there is another coherent dense wall. The structures in this survey support the view that galaxies generally lie on surfaces surrounding or nearly surrounding low-density regions or voids.