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551. Central black holes of spiral galaxies
ID:
ivo://CDS.VizieR/J/AJ/131/1236
Title:
Central black holes of spiral galaxies
Short Name:
J/AJ/131/1236
Date:
21 Oct 2021
Publisher:
CDS
Description:
Central black hole masses for 117 spiral galaxies representing morphological stages S0/a through Sc and taken from the large spectroscopic survey of Ho et al. (Cat. <J/ApJS/112/315>) are derived using Ks-band data from the Two Micron All Sky Survey. Black hole masses are found using a calibrated black hole-Ks bulge luminosity relation, while bulge luminosities are measured by means of a two-dimensional bulge-disk decomposition routine.
552. Central surface brightness of 30000 SDSS galaxies
ID:
ivo://CDS.VizieR/J/ApJ/722/L120
Title:
Central surface brightness of 30000 SDSS galaxies
Short Name:
J/ApJ/722/L120
Date:
21 Oct 2021
Publisher:
CDS
Description:
Disc central surface brightness for 30000 galaxies from the Sloan Digitized Sky Survey (SDSS) Data Release 7, in the r-band. Virtual Observatory methods and tools were used to define, retrieve and analyze the images for this unprecedentedly large sample classified as spiral galaxies in the LEDA catalogue. These parameters are also available for all other SDSS bands (u,g,i,z), and they can be retrieved from the Author.
553. Central surface densities in SPARC disk galaxies
ID:
ivo://CDS.VizieR/J/ApJ/827/L19
Title:
Central surface densities in SPARC disk galaxies
Short Name:
J/ApJ/827/L19
Date:
21 Oct 2021
Publisher:
CDS
Description:
We use the Spitzer Photometry and Accurate Rotation Curves (SPARC) database to study the relation between the central surface density of stars {Sigma}_*_(0) and dynamical mass {Sigma}_dyn_(0) in 135 disk galaxies (S0 to dIrr). We find that {Sigma}_dyn_(0) correlates tightly with {Sigma}_*_(0) over 4dex. This central density relation can be described by a double power law. High surface brightness galaxies are consistent with a 1:1 relation, suggesting that they are self-gravitating and baryon dominated in the inner parts. Low surface brightness (LSB) galaxies systematically deviate from the 1:1 line, indicating that the dark matter contribution progressively increases but remains tightly coupled to the stellar one. The observed scatter is small (~0.2dex) and largely driven by observational uncertainties. The residuals show no correlations with other galaxy properties like stellar mass, size, or gas fraction.
554. 90 cepheid candidates nearby NGC 6814
ID:
ivo://CDS.VizieR/J/ApJ/885/161
Title:
90 cepheid candidates nearby NGC 6814
Short Name:
J/ApJ/885/161
Date:
08 Mar 2022
Publisher:
CDS
Description:
We present a Cepheid-based distance to the nearby Seyfert galaxy NGC6814 from Hubble Space Telescope observations. We obtained F555W and F814W imaging over the course of 12 visits with logarithmic time spacing in 2013 August-October. We detected and made photometric measurements for 16469 unique sources across all images in both filters, from which we identify 90 excellent Cepheid candidates spanning a range of periods of 13-84days. We find evidence for incompleteness in the detection of candidates at periods <21days. Based on the analysis of Cepheid candidates above the incompleteness limit, we determine a distance modulus for NGC6814 relative to the LMC of {mu}_rel,LMC_=13.200_-0.031_^+0.031^mag. Adopting the recent constraint of the distance modulus to the LMC determined by Pietrzynski et al., we find m-M=31.677_-0.041_^+0.041^ which gives a distance of 21.65{+/-}0.41Mpc to NGC6814.
555. Cepheids and companions in M33 from HST images
ID:
ivo://CDS.VizieR/J/AJ/144/113
Title:
Cepheids and companions in M33 from HST images
Short Name:
J/AJ/144/113
Date:
21 Oct 2021
Publisher:
CDS
Description:
A precise and accurate determination of the Hubble constant based on Cepheid variables requires proper characterization of many sources of systematic error. One of these is stellar blending, which biases the measured fluxes of Cepheids and the resulting distance estimates. We study the blending of 149 Cepheid variables in M33 by matching archival Hubble Space Telescope data with images obtained at the Wisconsin-Indiana-Yale-NOAO (WIYN) 3.5m telescope, which differ by a factor of 10 in angular resolution. We find that 55%+/-4% of the Cepheids have no detectable nearby companions that could bias the WIYN V-band photometry, while the fraction of Cepheids affected below the 10% level is 73%+/-4%. The corresponding values for the I band are 60%+/-4% and 72%+/-4%, respectively. We find no statistically significant difference in blending statistics as a function of period or surface brightness. Additionally, we report all the detected companions within 2" of the Cepheids (equivalent to 9pc at the distance of M33) which may be used to derive empirical blending corrections for Cepheids at larger distances.
556. Cepheids HST amplitudes in V- and H-band
ID:
ivo://CDS.VizieR/J/ApJ/896/L43
Title:
Cepheids HST amplitudes in V- and H-band
Short Name:
J/ApJ/896/L43
Date:
21 Mar 2022 07:02:57
Publisher:
CDS
Description:
The accuracy of the Hubble constant measured with extragalactic Cepheids depends on robust photometry and background estimation in the presence of stellar crowding. The conventional approach accounts for crowding by sampling backgrounds near Cepheids and assuming that they match those at their positions. We show a direct consequence of crowding by unresolved sources at Cepheid sites is a reduction in the fractional amplitudes of their light curves. We use a simple analytical expression to infer crowding directly from the light curve amplitudes of >200 Cepheids in three Type Ia supernovae hosts and NGC4258 as observed by Hubble Space Telescope-the first near-infrared amplitudes measured beyond the Magellanic Clouds. Where local crowding is minimal, we find near-infrared amplitudes match Milky Way Cepheids at the same periods. At greater stellar densities we find that the empirically measured amplitudes match the values predicted (with no free parameters) from crowding assessed in the conventional way from local regions, confirming their accuracy for estimating the background at the Cepheid locations. Extragalactic Cepheid amplitudes would need to be ~20% smaller than measured to indicate additional, unrecognized crowding as a primary source of the present discrepancy in H0. Rather, we find the amplitude data constrains a systematic mis-estimate of Cepheid backgrounds to be 0.029R+/-0.037mag, more than 5x smaller than the size of the present ~0.2mag tension in H0. We conclude that systematic errors in Cepheid backgrounds do not provide a plausible resolution to the Hubble tension.
557. Cepheids in M101 observed with HST
ID:
ivo://CDS.VizieR/J/ApJ/733/124
Title:
Cepheids in M101 observed with HST
Short Name:
J/ApJ/733/124
Date:
21 Oct 2021
Publisher:
CDS
Description:
We accurately determine a new Cepheid distance to M101 (NGC 5457) using archival Hubble Space Telescope (HST)/Advanced Camera for Surveys V and I time series photometry of two fields within the galaxy. We make a slight modification to the ISIS image subtraction package to obtain optimal differential light curves from HST data. We discovered 827 Cepheids with periods between 3 and 80 days, the largest extragalactic sample of Cepheids observed with HST by a factor of two. With this large Cepheid sample, we find that the relative distance of M101 from the Large Magellanic Cloud is {Delta}{mu}_LMC_=10.63+/-0.04 (random) +/-0.06 (systematic) mag. If we use the geometrically determined maser distance to NGC 4258 as our distance anchor, the distance modulus of M101 is {mu}_0_=29.04+/-0.05 (random) +/-0.18 (systematic) mag or D=6.4+/-0.2 (random) +/-0.5 (systematic) Mpc. The uncertainty is dominated by the maser distance estimate (+/-0.15mag), which should improve over the next few years.
558. Cepheids in M31 - PAndromeda Cepheid sample
ID:
ivo://CDS.VizieR/J/AJ/156/130
Title:
Cepheids in M31 - PAndromeda Cepheid sample
Short Name:
J/AJ/156/130
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the largest Cepheid sample in M31 based on the complete Pan-STARRS1 survey of Andromeda (PAndromeda) in the r_P1_, i_P1_, and g_P1_ bands. We find 2686 Cepheids with 1662 fundamental-mode Cepheids, 307 first-overtone Cepheids, 278 type II Cepheids, and 439 Cepheids with undetermined Cepheid type. Using the method developed by Kodric et al. (2013, , Cat. J/AJ/145/106), we identify Cepheids by using a three-dimensional parameter space of Fourier parameters of the Cepheid light curves combined with a color cut and other selection criteria. This is an unbiased approach to identify Cepheids and results in a homogeneous Cepheid sample. The period-luminosity relations obtained for our sample have smaller dispersions than in our previous work. We find a broken slope that we previously observed with HST data in Kodric et al. (2013, , Cat. J/AJ/145/106), albeit with a lower significance.
559. Cetus dSph RR Lyrae
ID:
ivo://CDS.VizieR/J/MNRAS/422/89
Title:
Cetus dSph RR Lyrae
Short Name:
J/MNRAS/422/89
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate the variable star content of the isolated, Local Group, dwarf spheroidal (dSph) galaxy Cetus. Multi-epoch, wide-field images collected with the Very Large Telescope/Visible Multiobject Spectrograph camera allowed us to detect 638 variable stars (630 RR Lyrae stars and eight anomalous Cepheids), 475 of which are new detections. We present a full catalogue of periods, amplitudes and mean magnitudes.
560. Cetus dSph stellar chemo-kinematics
ID:
ivo://CDS.VizieR/J/A+A/618/A122
Title:
Cetus dSph stellar chemo-kinematics
Short Name:
J/A+A/618/A122
Date:
21 Oct 2021
Publisher:
CDS
Description:
Cetus is an isolated, dwarf spheroidal (dSph) galaxy at a distance of 755kpc. In order to quantify its stellar chemo-kinematical properties, we observed individual red giants branch stars in Cetus with the Very Large Telescope (VLT) FORS2 instrument, in Mask eXchange Unit (MXU) configuration. The kinematic analysis shows that Cetus is a mainly pressure-supported ({sigma}_v_=11.0^+1.6^_-1.3_km/s), dark-matter-dominated system (M_1/2_/L_V_=23.9^+9.7^_-8.9_M_{sun}_/L_{sun}_) with no significant signs of internal rotation. We find Cetus to be a metal-poor system with a significant metallicity spread (median [Fe/H]=-1.71dex, median-absolute-deviation =0.49dex), as expected for its stellar mass. We report the presence of a mild metallicity gradient compatible with those found in other dSphs of the same luminosity; we trace the presence of a stellar population gradient also in the spatial distribution of stars in different evolutionary phases in ancillary photometric data. There are tentative indications of two chemo-kinematically distinct sub-populations, with the more metal-poor stars showing a hotter kinematics than the metal-richer ones. Our results add Cetus to the growing scatter in stellar-dark matter halo properties in low-mass galactic systems. The presence of a metallicity gradient akin to those found in similar systems inhabiting different environments may hint at metallicity gradients in Local Group early-type dwarfs being driven by internal mechanisms.

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