- ID:
- ivo://CDS.VizieR/J/ApJ/763/73
- Title:
- Surface density profiles of GOODS-South galaxies
- Short Name:
- J/ApJ/763/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present stellar mass surface density profiles of a mass-selected sample of 177 galaxies at 0.5<z<2.5, obtained using very deep Hubble Space Telescope optical and near-infrared data over the GOODS-South field, including recent CANDELS data. Accurate stellar mass surface density profiles have been measured for the first time for a complete sample of high-redshift galaxies more massive than 10^10.7^M_{sun}_. The key advantage of this study compared to previous work is that the surface brightness profiles are deconvolved for point-spread function smoothing, allowing accurate measurements of the structure of the galaxies. The surface brightness profiles account for contributions from complex galaxy structures such as rings and faint outer disks. Mass profiles are derived using radial rest-frame ug color profiles and a well-established empirical relation between these colors and the stellar mass-to-light ratio. We derive stellar half-mass radii from the mass profiles, and find that these are on average ~25% smaller than rest-frame g-band half-light radii. This average size difference of 25% is the same at all redshifts, and does not correlate with stellar mass, specific star formation rate, effective surface density, S\'ersic index, or galaxy size. Although on average the difference between half-mass size and half-light size is modest, for approximately 10% of massive galaxies this difference is more than a factor of two. These extreme galaxies are mostly extended, disk-like systems with large central bulges. These results are robust, but could be impacted if the central dust extinction becomes high. ALMA observations can be used to explore this possibility. These results provide added support for galaxy growth scenarios wherein massive galaxies at these epochs grow by accretion onto their outer regions.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/156/345
- Title:
- Surface photometry of BCD galaxies
- Short Name:
- J/ApJS/156/345
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results from an analysis of surface photometry of B, R, and H{alpha} images of a total of 114 nearby galaxies (v_helio_<4000km/s) drawn from the Palomar/Las Campanas Imaging Atlas of blue compact dwarf (BCD) galaxies. Surface brightness and color profiles for the complete sample have been obtained. We determine the exponential and Sersic profiles that best fit the surface brightness distribution of the underlying stellar population detected in these galaxies. We also compute the (B-R) color and total absolute magnitude of the underlying stellar population and compared them to the integrated properties of the galaxies in the sample.
- ID:
- ivo://CDS.VizieR/J/ApJS/244/21
- Title:
- Surface rotation & activity of Kepler stars. I.
- Short Name:
- J/ApJS/244/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Brightness variations due to dark spots on the stellar surface encode information about stellar surface rotation and magnetic activity. In this work, we analyze the Kepler long-cadence data of 26521 main-sequence stars of spectral types M and K in order to measure their surface rotation and photometric activity level. Rotation-period estimates are obtained by the combination of a wavelet analysis and autocorrelation function of the light curves. Reliable rotation estimates are determined by comparing the results from the different rotation diagnostics and four data sets. We also measure the photometric activity proxy S_ph_ using the amplitude of the flux variations on an appropriate timescale. We report rotation periods and photometric activity proxies for about 60% of the sample, including 4431 targets for which McQuillan+ (2014, J/ApJS/211/24) did not report a rotation period. For the common targets with rotation estimates in this study and in McQuillan+, our rotation periods agree within 99%. In this work, we also identify potential polluters, such as misclassified red giants and classical pulsator candidates. Within the parameter range we study, there is a mild tendency for hotter stars to have shorter rotation periods. The photometric activity proxy spans a wider range of values with increasing effective temperature. The rotation period and photometric activity proxy are also related, with S_ph_ being larger for fast rotators. Similar to McQuillan+, we find a bimodal distribution of rotation periods.
- ID:
- ivo://CDS.VizieR/J/MNRAS/469/3444
- Title:
- Survey of Centaurus A's Baryonic Structures II.
- Short Name:
- J/MNRAS/469/3444
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New wide-field u'g'r'i'z' Dark Energy Camera observations centred on the nearby giant elliptical galaxy NGC 5128 covering ~21 deg^2^ are used to compile a new catalogue of ~3200 globular clusters (GCs). We report 2404 newly identified candidates, including the vast majority within ~140kpc of NGC 5128. We find evidence for a transition at a galactocentric radius of R_gc_~=55kpc from GCs 'intrinsic' to NGC 5128 to those likely to have been accreted from dwarf galaxies or that may transition to the intragroup medium of the Centaurus A galaxy group. We fit power-law surface number density profiles of the form {Sigma}_N,R_gc_{prop.to}R_gc_^{Gamma}^ and find that inside the transition radius, the red GCs are more centrally concentrated than the blue, with {Gamma}_inner,red_~=-1.78 and {Gamma}_inner,blue_~=-1.40, respectively. Outside this region both profiles flatten, more dramatically for the red GCs ({Gamma}_outer,red_~=-0.33) compared to the blue ({Gamma}_outer,blue_~= -0.61), although the former is more likely to suffer contamination by background sources. The median (g'-z')_0_=1.27mag colour of the inner red population is consistent with arising from the amalgamation of two giant galaxies each less luminous than present-day NGC 5128. Both inwards and outwards of the transition radius, we find the fraction of blue GCs to dominate over the red GCs, indicating a lively history of minor mergers. Assuming the blue GCs to originate primarily in dwarf galaxies, we model the population required to explain them, while remaining consistent with NGC 5128's present-day spheroid luminosity. We find that several dozen dwarfs of luminosities L_dw,V_~= 10^6-9.3^L_V,{sun}_, following a Schechter luminosity function with a faint-end slope of -1.50<={alpha}<=-1.25 is favoured, many of which may have already been disrupted in NGC 5128's tidal field.
- ID:
- ivo://CDS.VizieR/J/A+A/296/665
- Title:
- Survey of optically variables QSOs
- Short Name:
- J/A+A/296/665
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe a survey for variable QSOs carried out for 15 years with the UK Schmidt telescope, using IIIaJ plates exposed behind a Schott GG395 filter. Objects brighter than B=21.0 on a reference plate and displaying a peak to peak amplitude of variability larger than B=0.35mag are selected. Plates in U, V, R and I were also obtained.
- ID:
- ivo://CDS.VizieR/J/ApJS/219/27
- Title:
- Surveys of asteroid rotation periods using iPTF
- Short Name:
- J/ApJS/219/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Two dedicated asteroid rotation-period surveys have been carried out in the R band with ~20 minute cadence using the intermediate Palomar Transient Factory (iPTF) during 2014 January 6-9 and February 20-23. The total survey area covered 174deg^2^ in the ecliptic plane. Reliable rotation periods for 1438 asteroids are obtained from a larger data set of 6551 mostly main-belt asteroids, each with >=10 detections. Analysis of 1751, PTF-based, reliable rotation periods clearly shows the spin barrier at ~2hr for rubble-pile asteroids. We found a new large super-fast rotator, 2005 UW163, and another five candidates as well. For asteroids of 3<D<15km, our spin-rate distribution shows a number decrease along with frequency after 5 rev/day, which is consistent with the results of the Asteroid Light Curve Database. The discrepancy between our work and that of Pravec et al. (update 2014 April 20) comes mainly from asteroids with {Delta}_m_<0.2mag, which could be the result of different survey strategies. For asteroids with D<3km, we see a significant number drop at f=6rev/day. The relatively short YORP effect timescale for small asteroids could have spun up those elongated objects to reach their spin-rate limit resulting in breakup to create such a number deficiency. We also see that the C-type asteroids show a smaller spin-rate limit than the S-type, which agrees with the general impression that C-type asteroids have a lower bulk density than S-type asteroids.
- ID:
- ivo://CDS.VizieR/J/AN/325/424
- Title:
- SV Cam VB differential photometry
- Short Name:
- J/AN/325/424
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present analysis and spot solutions based on yet unpublished B and V photoelectric observations on the active binary system SV Cam, carried out at Piszkesteto Mountain Station of Konkoly Observatory Budapest. The present spot solutions are based on the observed light curves in September 1993 and July 1994. Comparison of recent and older spot solutions - taken from the literature - suggests long term differences, but these divergences might be caused by some differences of the applied computational methods.
- ID:
- ivo://CDS.VizieR/J/ApJS/222/13
- Title:
- Swift AGN and Cluster Survey (SWCL). II. SDSS
- Short Name:
- J/ApJS/222/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study 203 (of 442) Swift AGN and Cluster Survey extended X-ray sources located in the SDSS DR8 footprint to search for galaxy over-densities in three-dimensional space using SDSS galaxy photometric redshifts and positions near the Swift cluster candidates. We find 104 Swift clusters with a >3{sigma} galaxy over-density. The remaining targets are potentially located at higher redshifts and require deeper optical follow-up observations for confirmation as galaxy clusters. We present a series of cluster properties including the redshift, brightest cluster galaxy (BCG) magnitude, BCG-to-X-ray center offset, optical richness, and X-ray luminosity. We also detect red sequences in ~85% of the 104 confirmed clusters. The X-ray luminosity and optical richness for the SDSS confirmed Swift clusters are correlated and follow previously established relations. The distribution of the separations between the X-ray centroids and the most likely BCG is also consistent with expectation. We compare the observed redshift distribution of the sample with a theoretical model, and find that our sample is complete for z<~0.3 and is still 80% complete up to z~0.4, consistent with the SDSS survey depth. These analysis results suggest that our Swift cluster selection algorithm has yielded a statistically well-defined cluster sample for further study of cluster evolution and cosmology. We also match our SDSS confirmed Swift clusters to existing cluster catalogs, and find 42, 23, and 1 matches in optical, X-ray, and Sunyaev-Zel'dovich catalogs, respectively, and so the majority of these clusters are new detections.
- ID:
- ivo://CDS.VizieR/J/ApJ/850/74
- Title:
- Swift/BAT AGN Spectroscopic Survey. I.
- Short Name:
- J/ApJ/850/74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first catalog and data release of the Swift-BAT AGN Spectroscopic Survey. We analyze optical spectra of the majority of the detected AGNs (77%, 642/836) based on their 14-195keV emission in the 70-month Swift-BAT all-sky catalog. This includes redshift determination, absorption and emission-line measurements, and black hole mass and accretion rate estimates for the majority of obscured and unobscured AGNs (74%, 473/642), with 340 measured for the first time. With ~90% of sources at z<0.2, the survey represents a significant advance in the census of hard X-ray-selected AGNs in the local universe. In this first catalog paper, we describe the spectroscopic observations and data sets, and our initial spectral analysis. The FWHMs of the emission lines show broad agreement with the X-ray obscuration (~94%), such that Sy 1-1.8 have N_H_<10^21.9^cm^-2^, and Seyfert 2 have N_H_>10^21.9^cm^-2^. Seyfert 1.9, however, show a range of column densities. Compared to narrow-line AGNs in the SDSS, the X-ray-selected AGNs have a larger fraction of dusty host galaxies (H{alpha}/H{beta}>5), suggesting that these types of AGN are missed in optical surveys. Using the [OIII]{lambda}5007/H{beta} and [NII]{lambda}6583/H{alpha} emission-line diagnostic, about half of the sources are classified as Seyferts; ~15% reside in dusty galaxies that lack an H{beta} detection, but for which the upper limits on line emission imply either a Seyfert or LINER, ~15% are in galaxies with weak or no emission lines despite high-quality spectra, and a few percent each are LINERS, composite galaxies, H II regions, or in known beamed AGNs.
- ID:
- ivo://CDS.VizieR/J/ApJ/864/84
- Title:
- Swift follow-up obs. of the TXS 0506+056 blazar
- Short Name:
- J/ApJ/864/84
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Detection of the IceCube-170922A neutrino coincident with the flaring blazar TXS 0506+056, the first and only ~3{sigma} high-energy neutrino source association to date, offers a potential breakthrough in our understanding of high-energy cosmic particles and blazar physics. We present a comprehensive analysis of TXS 0506+056 during its flaring state, using newly collected Swift, NuSTAR, and X-shooter data with Fermi observations and numerical models to constrain the blazar's particle acceleration processes and multimessenger (electromagnetic (EM) and high-energy neutrino) emissions. Accounting properly for EM cascades in the emission region, we find a physically consistent picture only within a hybrid leptonic scenario, with {gamma}-rays produced by external inverse-Compton processes and high-energy neutrinos via a radiatively subdominant hadronic component. We derive robust constraints on the blazar's neutrino and cosmic-ray emissions and demonstrate that, because of cascade effects, the 0.1-100keV emissions of TXS 0506+056 serve as a better probe of its hadronic acceleration and high-energy neutrino production processes than its GeV-TeV emissions. If the IceCube neutrino association holds, physical conditions in the TXS 0506+056 jet must be close to optimal for high-energy neutrino production, and are not favorable for ultrahigh-energy cosmic-ray acceleration. Alternatively, the challenges we identify in generating a significant rate of IceCube neutrino detections from TXS 0506+056 may disfavor single-zone models, in which {gamma}-rays and high-energy neutrinos are produced in a single emission region. In concert with continued operations of the high-energy neutrino observatories, we advocate regular X-ray monitoring of TXS 0506+056 and other blazars in order to test single-zone blazar emission models, clarify the nature and extent of their hadronic acceleration processes, and carry out the most sensitive possible search for additional multimessenger sources.
