- ID:
- ivo://CDS.VizieR/J/MNRAS/477/1708
- Title:
- Origins of post-starburst galaxies at z<0.05
- Short Name:
- J/MNRAS/477/1708
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Post-starburst galaxies can be identified via the presence of prominent Hydrogen Balmer absorption lines in their spectra. We present a comprehensive study of the origin of strong Balmer lines in a volume-limited sample of 189 galaxies with 0.01<z<0.05, log(M*/M_{sun}_)>9.5 and projected axial ratio b/a>0.32. We explore their structural properties, environments, emission lines, and star formation histories, and compare them to control samples of star-forming and quiescent galaxies, and simulated galaxy mergers. Excluding contaminants, in which the strong Balmer lines are most likely caused by dust-star geometry, we find evidence for three different pathways through the post-starburst phase, with most events occurring in intermediate-density environments: (1) a significant disruptive event, such as a gas-rich major merger, causing a starburst and growth of a spheroidal component, followed by quenching of the star formation (70 per cent of post-starburst galaxies at 9.5<log(M*/M_{sun}_)<10.5 and 60 per cent at log(M*/M_{sun}_)>10.5); (2) at 9.5<log(M*/M_{sun}_)<10.5, stochastic star formation in blue-sequence galaxies, causing a weak burst and subsequent return to the blue sequence (30 per cent); (3) at log(M*/M_{sun}_)>10.5, cyclic evolution of quiescent galaxies which gradually move towards the high-mass end of the red sequence through weak starbursts, possibly as a result of a merger with a smaller gas-rich companion (40 per cent). Our analysis suggests that active galactic nuclei (AGNs) are 'on' for 50 per cent of the duration of the post-starburst phase, meaning that traditional samples of post-starburst galaxies with strict emission-line cuts will be at least 50 per cent incomplete due to the exclusion of narrow-line AGNs.
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- ID:
- ivo://CDS.VizieR/J/AJ/142/145
- Title:
- Outer disks of S0-Sb gal. II. Surface-brigthness
- Short Name:
- J/AJ/142/145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present azimuthally averaged radial profiles of R-band surface brightness for a complete sample of 47 early-type, unbarred galaxies, as a complement to our previous study of early-type barred galaxies. Following very careful sky subtraction, the profiles can typically be determined down to brightness levels well below 27mag/arcsec^2^ and in the best cases below 28mag/arcsec^-2^. We classified the profiles according to the scheme used previously for the barred sample: Type I profiles are single unbroken exponential radial declines in brightness; Type II profiles ("truncations") have an inner shallow slope (usually exponential) which changes at a well-defined break radius to a steeper exponential; and Type III profiles ("antitruncations") have an inner exponential that is steeper, giving way to a shallower outer (usually exponential) decline. By combining these profiles with previous studies, we can make the first clear statements about the trends of outer-disk-profile types along the Hubble sequence (including both barred and unbarred galaxies), and their global frequencies.
- ID:
- ivo://CDS.VizieR/J/ApJS/144/47
- Title:
- Outer galaxy molecular cloud catalog
- Short Name:
- J/ApJS/144/47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Five College Radio Astronomy Observatory (FCRAO) Outer Galaxy Survey (OGS) of ^12^CO(J=1-0) emission was carried out between 1994May and 1997September, using the FCRAO focal plane array QUARRY (Erickson et al. 1992, IEEE Trans. 40, 1), and initially described by Heyer et al. (1998ApJS..115..241H). The OGS covers the Galactic area 102.5<l<141.5, -3<b<54, and the velocity range -152km/s<vlsr<40km/s, at 45'' spatial resolution sampled every 50.22'', and 0.98km/s velocity resolution (1.39km/s for l<106) sampled every 0.81km/s. The typical sensitivity of the OGS at these resolutions is 0.6K (T*_R_ temperature scale). The catalog was generated in a two-phase object identification procedure. The first phase consists of grouping pixels into contiguous structures above a radiation temperature threshold of 0.8K; the second phase decomposes the first-phase objects by an enhanced version of the CLUMPFIND algorithm, using dynamic thresholding, and again with a threshold of 0.8K used for discrimination. Basic attributes of the clouds (coordinates, bounding boxes, integrated intensities, peak observed temperatures) are tabulated in the catalog. A two-dimensional elliptical Gaussian is fitted to the velocity- integrated map of each cloud; the major and minor axis sizes and major axis position angles thus derived are included in the catalog. To the spatially integrated emission line of each cloud, a Gaussian profile is fitted to measure the global linewidth. Model Gaussian clouds, truncated at 0.8K, are examined to determine the effects of biases on measured quantities, induced by truncation. Coupled with detailed analysis of the catalogued clouds, statistical corrections for the effects of truncation on measured sizes, linewidths, and integrated intensities are derived and applied, along with corrections for the effects of finite resolution on the measured attributes. The catalogued emission accounts for 76.4% of the total emission in the Outer Galaxy Survey. The deficit is shown to arise mainly from low-intensity emission on the periphery of larger objects, rather than from a large number of small and/or low-intensity features.
- ID:
- ivo://CDS.VizieR/J/ApJ/809/91
- Title:
- Outflows in sodium excess objects
- Short Name:
- J/ApJ/809/91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Van Dokkum and Conroy (2010Natur.468..940V) revisited the unexpectedly strong NaI lines at 8200{AA} found in some giant elliptical galaxies and interpreted them as evidence for an unusually bottom-heavy initial mass function. Jeong et al. (2013, J/ApJS/208/7) later found a large population of galaxies showing equally extraordinary Na D doublet absorption lines at 5900{AA} (Na D excess objects: NEOs) and showed that their origins can be different for different types of galaxies. While a Na D excess seems to be related to the interstellar medium (ISM) in late-type galaxies, smooth-looking early-type NEOs show little or no dust extinction and hence no compelling signs of ISM contributions. To further test this finding, we measured the Doppler components in the Na D lines. We hypothesized that the ISM would have a better (albeit not definite) chance of showing a blueshift Doppler departure from the bulk of the stellar population due to outflow caused by either star formation or AGN activities. Many of the late-type NEOs clearly show blueshift in their Na D lines, which is consistent with the former interpretation that the Na D excess found in them is related to gas outflow caused by star formation. On the contrary, smooth-looking early-type NEOs do not show any notable Doppler components, which is also consistent with the interpretation of Jeong et al. that the Na D excess in early-type NEOs is likely not related to ISM activities but is purely stellar in origin.
- ID:
- ivo://CDS.VizieR/J/A+A/623/A7
- Title:
- Oxygen abundance in disk galaxies
- Short Name:
- J/A+A/623/A7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We examine the possible dependence of the radial oxygen abundance distribution on non-axisymmetrical structures (bar/spirals) and other macroscopic parameters such as the mass, the optical radius R25, the color g-r, and the surface brightness of the galaxy. A sample of disk galaxies from the third data release of the Calar Alto Legacy Integral Field Area Survey (CALIFA DR3) is considered. We adopted the Fourier amplitude A2 of the surface brightness as a quantitative characteristic of the strength of nonaxisymmetric structures in a galactic disk, in addition to the commonly used morphologic division for A, AB, and B types based on the Hubble classification. To distinguish changes in local oxygen abundance caused by the non-axisymmetrical structures, the multiparametric mass-metallicity relation was constructed as a function of parameters such as the bar/spiral pattern strength, the disk size, color index g-r in the Sloan Digital Sky Survey (SDSS) bands, and central surface brightness of the disk. The gas-phase oxygen abundance gradient is determined by using the R calibration We find that there is no significant impact of the non-axisymmetric structures such as a bar and/or spiral patterns on the local oxygen abundance and radial oxygen abundance gradient of disk galaxies. Galaxies with higher mass, however, exhibit flatter oxygen abundance gradients in units of dex/kpc, but this effect is significantly less prominent for the oxygen abundance gradients in units of dex/R25 and almost disappears when the inner parts are avoided (R>0.25R25). We show that the oxygen abundance in the central part of the galaxy depends neither on the optical radius R25 nor on the color g-r or the surface brightness of the galaxy. Instead, outside the central part of the galaxy, the oxygen abundance increases with g-r value and central surface brightness of the disk.
- ID:
- ivo://CDS.VizieR/J/MNRAS/462/2715
- Title:
- Oxygen abundance maps of CALIFA galaxies
- Short Name:
- J/MNRAS/462/2715
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We construct maps of the oxygen abundance distribution across the discs of 88 galaxies using Calar Alto Legacy Integral Field Area survey (CALIFA) Data Release 2 (DR2) spectra. The position of the centre of a galaxy (coordinates on the plate) was also taken from the CALIFA DR2. The galaxy inclination, the position angle of the major axis, and the optical radius were determined from the analysis of the surface brightnesses in the Sloan Digital Sky Survey (SDSS) g and r bands of the photometric maps of SDSS Data Release 9. We explore the global azimuthal abundance asymmetry in the discs of the CALIFA galaxies and the presence of a break in the radial oxygen abundance distribution. We found that there is no significant global azimuthal asymmetry for our sample of galaxies, i.e. the asymmetry is small, usually lower than 0.05dex. The scatter in oxygen abundances around the abundance gradient has a comparable value, <~0.05dex. A significant (possibly dominant) fraction of the asymmetry can be attributed to the uncertainties in the geometrical parameters of these galaxies. There is evidence for a flattening of the radial abundance gradient in the central part of 18 galaxies. We also estimated the geometric parameters (coordinates of the centre, the galaxy inclination and the position angle of the major axis) of our galaxies from the analysis of the abundance map. The photometry-map-based and the abundance-map-based geometrical parameters are relatively close to each other for the majority of the galaxies but the discrepancy is large for a few galaxies with a flat radial abundance gradient.
- ID:
- ivo://CDS.VizieR/J/MNRAS/450/2692
- Title:
- Parameters of galactic globular clusters
- Short Name:
- J/MNRAS/450/2692
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use our Galactic Globular Cluster Catalog (G2C2) photometry for 111 Galactic globular clusters (GCs) in g and z, as well as r and i photometry for a subset of 60 GCs and u photometry for 22 GCs, to determine the structural parameters assuming King models. In general, the resulting core radii are in good comparison with the current literature values. However, our half-light radii are slightly lower than the literature. The concentrations (and therefore also the tidal radii) are poorly constrained mostly because of the limited radial extent of our imaging. Therefore, we extensively discuss the effects of a limited field of view on the derived parameters using mosaicked Sloan Digital Sky Survey data, which do not suffer from this restriction. We also illustrate how red giant branch (RGB) stars in cluster cores can stochastically induce artificial peaks in the surface brightness profiles. The issues related to these bright stars are scrutinized based on both our photometry and simulated clusters. We also examine colour gradients and find that the strongest central colour gradients are caused by central RGB stars and thus not representative for the cluster light or colour distribution. We recover the known relation between the half-light radius and the Galactocentric distance in the g band, but find a lower slope for redder filters. We did not find a correlation between the scatter on this relation and other cluster properties. We find tentative evidence for a correlation between the half-light radii and the [Fe/H], with metal-poor GCs being larger than metal-rich GCs. However, we conclude that this trend is caused by the position of the clusters in the Galaxy, with metal-rich clusters being more centrally located.
- ID:
- ivo://CDS.VizieR/J/ApJS/107/97
- Title:
- Parameters of 2447 southern spirals
- Short Name:
- J/ApJS/107/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- I-band luminosities, rotational velocities, and redshifts of 1092 spiral galaxies have been measured by CCD photometry and Halpha spectroscopy using the 1m and 2.3m telescopes at Siding Spring Observatory, respectively. The results are tabulated. Luminosity profiles and Halpha rotation curves are given for the galaxies. When these results are combined with similar data for 1355 spiral galaxies published previously (Mathewson, Ford, & Buchhorn, hereafter Paper I, 1992ApJS...81..413M), it provides a large, uniform, and unique data set with which to measure, via the Tully-Fisher relation, the peculiar velocities of galaxies in the local universe to a distance of 11,000km/s (Mathewson & Ford, in Proc. Heron Island Workshop on Peculiar Velocities in the Universe). Taking advantage of the opportunity for publishing this data in machine-readable form, in the CD-ROM, we have also published similar data for the 1355 galaxies in Paper I.
- ID:
- ivo://CDS.VizieR/J/A+A/505/1049
- Title:
- Parkes HI observations behind Milky Way II
- Short Name:
- J/A+A/505/1049
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As part of our programme to map the large-scale distribution of galaxies behind the southern Milky Way, we observed 314 optically-selected, partially-obscured galaxies in the Zone of Avoidance (ZOA) in the Crux and Great Attractor (GA) regions. An additional 29 galaxies were observed in the Vela ZOA survey region (because of the small numbers they are not discussed any further). The observations were conducted with the Parkes 64m (210 ft) radio telescope, in a single-pixel pointed mode, reaching an rms noise level of typically 2-6mJy over the velocity search range of 400<v<10500km/s. A total of 162 galaxies were detected (plus 14 galaxies in the Vela region). The detection rate is slightly higher than for the Hydra/Antlia region (52% versus 45%) observed in the same way.
- ID:
- ivo://CDS.VizieR/J/MNRAS/474/1909
- Title:
- Passive spiral galaxies quench
- Short Name:
- J/MNRAS/474/1909
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We examine the properties of a sample of 35 nearby passive spiral galaxies in order to determine their dominant quenching mechanism(s). All five low-mass (M*<1x10^10^M_{sun}_) passive spiral galaxies are located in the rich Virgo cluster. This is in contrast to low-mass spiral galaxies with star formation, which inhabit a range of environments. We postulate that cluster-scale gas stripping and heating mechanisms operating only in rich clusters are required to quench low-mass passive spirals, and ram-pressure stripping and strangulation are obvious candidates. For higher mass passive spirals, while trends are present, the story is less clear. The passive spiral bar fraction is high: 74+/-15 per cent, compared with 36+/-5 per cent for a mass, redshift and T-type matched comparison sample of star-forming spiral galaxies. The high mass passive spirals occur mostly, but not exclusively, in groups, and can be central or satellite galaxies. The passive spiral group fraction of 74+/-15 per cent is similar to that of the comparison sample of star-forming galaxies at 61+/-7 per cent. We find evidence for both quenching via internal structure and environment in our passive spiral sample, though some galaxies have evidence of neither. From this, we conclude no one mechanism is responsible for quenching star formation in passive spiral galaxies - rather, a mixture of mechanisms is required to produce the passive spiral distribution we see today.
