- ID:
- ivo://CDS.VizieR/J/ApJ/893/11
- Title:
- Massive star variability in M31 from iPTF
- Short Name:
- J/ApJ/893/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using data from the (intermediate) Palomar Transient Factory (iPTF), we characterize the time variability of ~500 massive stars in M31. Our sample is those stars that are spectrally typed by Massey and collaborators, including Luminous Blue Variables, Wolf-Rayets, and warm and cool supergiants. We use the high-cadence, long-baseline (~5yr) data from the iPTF survey, coupled with data-processing tools that model complex features in the light curves. We find widespread photometric (R-band) variability in the upper Hertzsprung Russell diagram (or CMD) with an increasing prevalence of variability with later spectral types. Red stars (V-I>1.5) exhibit larger amplitude fluctuations than their bluer counterparts. We extract a characteristic variability timescale, t_ch_, via wavelet transformations that are sensitive to both continuous and localized fluctuations. Cool supergiants are characterized by longer timescales (>100 days) than the hotter stars. The latter have typical timescales of tens of days but cover a wider range, from our resolution limit of a few days to longer than 100 days. Using a 60 night block of data straddling two nights with a cadence of around 2 minutes, we extracted t_ch_ in the range 0.1-10 days with amplitudes of a few percent for 13 stars. Though there is broad agreement between the observed variability characteristics in the different parts of the upper CMD with theoretical predictions, detailed comparison requires models with a more comprehensive treatment of the various physical processes operating in these stars, such as pulsation, subsurface convection, and the effect of binary companions.
Number of results to display per page
Search Results
2132. MASSIVE Survey. VII.
- ID:
- ivo://CDS.VizieR/J/MNRAS/471/1428
- Title:
- MASSIVE Survey. VII.
- Short Name:
- J/MNRAS/471/1428
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse the environmental properties of 370 local early-type galaxies (ETGs) in the MASSIVE and ATLAS^3D^ surveys, two complementary volume-limited integral-field spectroscopic (IFS) galaxy surveys spanning absolute K-band magnitude - 21.5>=M_K_>=-26.6, or stellar mass 8*10^9^<~M*<~2*10^12^M{sun}. We find these galaxies to reside in a diverse range of environments measured by four methods: group membership (whether a galaxy is a brightest group/cluster galaxy, satellite or isolated), halo mass, large-scale mass density (measured over a few Mpc) and local mass density (measured within the Nth neighbour). The spatially resolved IFS stellar kinematics provide robust measurements of the spin parameter {lambda}_e_ and enable us to examine the relationship among {lambda}_e_, M* and galaxy environment. We find a strong correlation between {lambda}_e_ and M*, where the average {lambda}_e_ decreases from ~0.4 to below 0.1 with increasing mass, and the fraction of slow rotators f_slow_ increase from ~10 to 90 per cent. We show for the first time that at fixed M*, there are almost no trends between galaxy spin and environment; the apparent kinematic morphology-density relation for ETGs is therefore primarily driven by M* and is accounted for by the joint correlations between M* and spin, and between M* and environment. A possible exception is that the increased f_slow_ at high local density is slightly more than expected based only on these joint correlations. Our results suggest that the physical processes responsible for building up the present-day stellar masses of massive galaxies are also very efficient at reducing their spin, in any environment.
- ID:
- ivo://CDS.VizieR/J/ApJ/874/66
- Title:
- MASSIVE survey. XII. Early-type galaxy gradients
- Short Name:
- J/ApJ/874/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measure the stellar populations as a function of the radius for 90 early-type galaxies (ETGs) in the MASSIVE survey, a volume-limited integral-field spectroscopic (IFS) galaxy survey targeting all northern-sky ETGs with an absolute K-band magnitude of M_K_{<}-25.3mag or a stellar mass of M_*_>~4x10^11^M_{sun}_, within 108Mpc. We are able to measure reliable stellar population parameters for individual galaxies out to 10-20kpc (1-3R_e_) depending on the galaxy. Focusing on ~R_e_ (~10kpc), we find significant correlations between the abundance ratios, {sigma}, and M^*^ at a large radius, but we also find that the abundance ratios saturate in the highest-mass bin. We see a strong correlation between the kurtosis of the line-of-sight velocity distribution (h4) and the stellar population parameters beyond R_e_. Galaxies with higher radial anisotropy appear to be older, with metal-poorer stars and enhanced [{alpha}/Fe]. We suggest that the higher radial anisotropy may derive from more accretion of small satellites. Finally, we see some evidence for correlations between environmental metrics (measured locally and on >5Mpc scales) and the stellar populations, as expected if satellites are quenched earlier in denser environments.
- ID:
- ivo://CDS.VizieR/J/ApJ/772/25
- Title:
- Massive SZE clusters observations with ACT
- Short Name:
- J/ApJ/772/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first dynamical mass estimates and scaling relations for a sample of Sunyaev-Zel'dovich effect (SZE) selected galaxy clusters. The sample consists of 16 massive clusters detected with the Atacama Cosmology Telescope (ACT) over a 455deg^2^ area of the southern sky. Deep multi-object spectroscopic observations were taken to secure intermediate-resolution (R~700-800) spectra and redshifts for {approx}60 member galaxies on average per cluster. The dynamical masses M_200c_ of the clusters have been calculated using simulation-based scaling relations between velocity dispersion and mass. The sample has a median redshift z=0.50 and a median mass M_200c_~12x10^14^h_70_^-1^M_{sun}_ with a lower limit M_200c_~6x10^14^h_70_^-1^M_{sun}_, consistent with the expectations for the ACT southern sky survey. These masses are compared to the ACT SZE properties of the sample, specifically, the match-filtered central SZE amplitude {overline}{y_0_}, the central Compton parameter y_0_, and the integrated Compton signal Y_200c_, which we use to derive SZE-mass scaling relations. All SZE estimators correlate with dynamical mass with low intrinsic scatter (<~20%), in agreement with numerical simulations. We explore the effects of various systematic effects on these scaling relations, including the correlation between observables and the influence of dynamically disturbed clusters. Using the three-dimensional information available, we divide the sample into relaxed and disturbed clusters and find that ~50% of the clusters are disturbed. There are hints that disturbed systems might bias the scaling relations, but given the current sample sizes, these differences are not significant; further studies including more clusters are required to assess the impact of these clusters on the scaling relations.
- ID:
- ivo://CDS.VizieR/J/A+A/539/A91
- Title:
- MASSIV I. Sample properties
- Short Name:
- J/A+A/539/A91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the global properties (redshift, SED-based stellar mass and star formation rate, [OII]3727 flux and equivalent width) of the MASSIV sample. It contains 84 star-forming galaxies in the redshift range 0.9<z<1.8 selected from the VVDS and observed with the SINFONI/VLT integral-field spectrograph. The main aims of the MASSIV survey is to probe the kinematics and chemical properties of a significant and representative sample of high-redshift galaxies with star formation rate >5M_{sun}_/yr.
- ID:
- ivo://CDS.VizieR/J/MNRAS/469/2121
- Title:
- Mass-metallicity relation revisited with CALIFA
- Short Name:
- J/MNRAS/469/2121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an updated version of the mass-metallicity (MZ) relation using integral field spectroscopy data obtained from 734 galaxies observed by the CALIFA survey. These unparalleled spatially resolved spectroscopic data allow us to determine the metallicity at the same physical scale (R_e_) for different calibrators. We obtain MZ relations with similar shapes for all calibrators, once the scalefactors among them are taken into account. We do not find any significant secondary relation of the MZ relation with either the star formation rate (SFR) or the specific SFR for any of the calibrators used in this study, based on the analysis of the residuals of the best-fitted relation. However, we do see a hint for an (s)SFR-dependent deviation of the MZ relation at low masses (M<10^9.5^M_{sun}_), where our sample is not complete. We are thus unable to confirm the results by Mannucci et al. (2010), although we cannot exclude that this result is due to the differences in the analysed data sets. In contrast, our results are inconsistent with the results by Lara-Lopez et al. (2010), and we can exclude the presence of an SFR-mass-oxygen abundance fundamental plane. These results agree with previous findings suggesting that either (1) the secondary relation with the SFR could be induced by an aperture effect in single fibre/aperture spectroscopic surveys, (2) it could be related to a local effect confined to the central regions of galaxies or (3) it is just restricted to the low-mass regime, or a combination of the three effects.
- ID:
- ivo://CDS.VizieR/J/AJ/152/157
- Title:
- Mass models for 175 disk galaxies with SPARC
- Short Name:
- J/AJ/152/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We introduce SPARC (Spitzer Photometry and Accurate Rotation Curves): a sample of 175 nearby galaxies with new surface photometry at 3.6{mu}m and high-quality rotation curves from previous HI/H{alpha} studies. SPARC spans a broad range of morphologies (S0 to Irr), luminosities (~5dex), and surface brightnesses (~4dex). We derive [3.6] surface photometry and study structural relations of stellar and gas disks. We find that both the stellar mass-HI mass relation and the stellar radius-HI radius relation have significant intrinsic scatter, while the HI mass-radius relation is extremely tight. We build detailed mass models and quantify the ratio of baryonic to observed velocity (V_bar_/V_obs_) for different characteristic radii and values of the stellar mass-to-light ratio ({Upsilon}_*_) at [3.6]. Assuming {Upsilon}_*_{simeq}0.5M_{Sun}_/L_{Sun}_ (as suggested by stellar population models), we find that (i) the gas fraction linearly correlates with total luminosity; (ii) the transition from star-dominated to gas-dominated galaxies roughly corresponds to the transition from spiral galaxies to dwarf irregulars, in line with density wave theory; and (iii) V_bar_/V_obs_ varies with luminosity and surface brightness: high-mass, high-surface-brightness galaxies are nearly maximal, while low-mass, low-surface-brightness galaxies are submaximal. These basic properties are lost for low values of {Upsilon}_*_ {simeq}0.2M_{Sun}_/L_{Sun}_ as suggested by the DiskMass survey. The mean maximum-disk limit in bright galaxies is {Upsilon}_*_{simeq}0.7M_{Sun}_/L_{Sun}_ at [3.6]. The SPARC data are publicly available and represent an ideal test bed for models of galaxy formation.
- ID:
- ivo://CDS.VizieR/J/MNRAS/477/4187
- Title:
- Mass models of 171 galaxies
- Short Name:
- J/MNRAS/477/4187
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Mass models of a sample of 171 low- and high-surface brightness galaxies are presented in the context of the cold dark matter (CDM) theory using the NFW dark matter halo density distribution to extract a new concentration-viral mass relation (c-M_vir_). The rotation curves (RCs) are calculated from the total baryonic matter based on the 3.6{mu}m-band surface photometry, the observed distribution of neutral hydrogen, and the dark halo, in which the three adjustable parameters are the stellar mass-to-light ratio, halo concentration, and virial mass. Although accounting for a NFW dark halo profile can explain RC observations, the implied c-M_vir_ relation from RC analysis strongly disagrees with that resulting from different cosmological simulations. Also, the M/L-colour correlation of the studied galaxies is inconsistent with that expected from stellar population synthesis models with different stellar initial mass functions. Moreover, we show that the best-fitting stellar M/L ratios of 51 galaxies (30 per cent of our sample) have unphysically negative values in the framework of the {Lambda}CDM theory. This can be interpreted as a serious crisis for this theory. This suggests either that the commonly used NFW halo profile, which is a natural result of {Lambda}CDM cosmological structure formation, is not an appropriate profile for the dark haloes of galaxies, or, new dark matter physics or alternative gravity models are needed to explain the rotational velocities of disc galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/131/1942
- Title:
- 2MASS observations of IRAS 1Jy ULIRGs
- Short Name:
- J/AJ/131/1942
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Two Micron All Sky Survey observation of the IRAS 1Jy sample of ultraluminous infrared galaxies (ULIRGs) is presented in this paper. Together with the IRAS photometric data, the properties and energy sources of the IRAS 1Jy sample of ULIRGs in the near- and far-infrared are discussed.
- ID:
- ivo://CDS.VizieR/J/other/BSAO/57.5
- Title:
- 2MASS-selected Flat Galaxy Catalog (2MFGC)
- Short Name:
- J/other/BSAO/57.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An all-sky catalog of 18020 disc-like galaxies is presented. The galaxies are selected from the Extended Source Catalog of the Two Micron All-Sky Survey (XSC 2MASS) basing on their 2MASS axial ratio a/b>=3. The Catalog contains data on magnitudes of a galaxy in the J, H, Ks bands, its axial ratio, positional angle, index of luminosity concentration, as well as identification of the galaxy with the LEDA and the NED databases. Unlike the available optical catalogs, the new 2MFGC catalog seems to be more suitable to study cosmic streaming on a scale of z~0.1. The dipole moment of distribution of the bright (K<11mag) 2MFGC objects (l=227{deg}, b=41{deg} or SGL=90{deg}, SGB=-43{deg}) lies within statistical errors (+/-15{deg}) in the direction of the IRAS dipole and the optical RFGC dipole.
