- ID:
- ivo://CDS.VizieR/J/ApJ/875/60
- Title:
- SAMI Galaxy Survey: early-type gal. in A119 & A168
- Short Name:
- J/ApJ/875/60
- Date:
- 08 Mar 2022 13:03:14
- Publisher:
- CDS
- Description:
- We investigate the kinematic alignments of luminous early-type galaxies (M_r_<=-19.5mag) in A119 and A168 using the kinematic position angles (PA_kin_) from the Sydney-AAO Multi-object Integral-field spectrograph (SAMI) survey data, motivated by the implication of the galaxy spin alignment in a cosmological context. To increase the size of our sample for statistical significance, we also use the photometric position angles (PA_phot_) for galaxies that have not been observed by SAMI, if their ellipticities are higher than 0.15. Our luminous early-type galaxies tend to prefer the specific position angles in both clusters, confirming the results of Kim+ (2018ApJ...860L...3K), who recently found the kinematic alignment of early-type galaxies in the Virgo cluster based on the ATLAS3D integral-field spectroscopic data. This alignment signal is more prominent for galaxies in the projected phase-space regions dominated by infalling populations. Furthermore, the alignment angles are closely related to the directions of the filamentary structures around clusters. The results lead us to conclude that many cluster early-type galaxies are likely to be accreted along filaments while maintaining their spin axes, which are predetermined before cluster infall.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/835/104
- Title:
- SAMI Galaxy Survey: rotators classification
- Short Name:
- J/ApJ/835/104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent cosmological hydrodynamical simulations suggest that integral field spectroscopy can connect the high-order stellar kinematic moments h_3_ (~skewness) and h_4_ (~kurtosis) in galaxies to their cosmological assembly history. Here, we assess these results by measuring the stellar kinematics on a sample of 315 galaxies, without a morphological selection, using two-dimensional integral field data from the SAMI Galaxy Survey. Proxies for the spin parameter ({lambda}R_e_) and ellipticity ({epsilon}_e_) are used to separate fast and slow rotators; there exists a good correspondence to regular and non-regular rotators, respectively, as also seen in earlier studies. We confirm that regular rotators show a strong h_3_ versus V/{sigma} anti-correlation, whereas quasi-regular and non-regular rotators show a more vertical relation in h_3_ and V/{sigma}. Motivated by recent cosmological simulations, we develop an alternative approach to kinematically classify galaxies from their individual h_3_ versus V/{sigma} signatures. Within the SAMI Galaxy Survey, we identify five classes of high-order stellar kinematic signatures using Gaussian mixture models. Class 1 corresponds to slow rotators, whereas Classes 2-5 correspond to fast rotators. We find that galaxies with similar {lambda}R_e_-{epsilon}_e_ values can show distinctly different h_3_-V/{sigma} signatures. Class 5 objects are previously unidentified fast rotators that show a weak h_3_ versus V/{sigma} anti-correlation. From simulations, these objects are predicted to be disk-less galaxies formed by gas-poor mergers. From morphological examination, however, there is evidence for large stellar disks. Instead, Class 5 objects are more likely disturbed galaxies, have counter-rotating bulges, or bars in edge-on galaxies. Finally, we interpret the strong anti-correlation in h_3_ versus V/{sigma} as evidence for disks in most fast rotators, suggesting a dearth of gas-poor mergers among fast rotators.
- ID:
- ivo://CDS.VizieR/J/ApJ/804/7
- Title:
- SaMOSA: optical spectroscopy of 7 Fermi blazars
- Short Name:
- J/ApJ/804/7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present multi-epoch optical spectroscopy of seven southern Fermi-monitored blazars from 2008 to 2013 using the Small and Medium Aperture Research Telescope System (SMARTS), with supplemental spectroscopy and polarization data from the Steward Observatory. We find that the emission lines are much less variable than the continuum; four of seven blazars had no detectable emission line variability over the 5 yr observation period. This is consistent with photoionization primarily by an accretion disk, allowing us to use the lines as a probe of disk activity. Comparing optical emission line flux with Fermi {gamma}-ray flux and optical polarized flux, we investigate whether relativistic jet variability is related to the accretion flow. In general, we see no such dependence, suggesting that the jet variability is likely caused by internal processes like turbulence or shock acceleration rather than a variable accretion rate. However, three sources showed statistically significant emission line flares in close temporal proximity to very large Fermi {gamma}-ray flares. While we do not have sufficient emission line data to quantitatively assess their correlation with the {gamma}-ray flux, it appears that in some cases the jet might provide additional photoionizing flux to the broad-line region (BLR), which implies that some {gamma}-rays are produced within the BLR, at least for these large flares.
- ID:
- ivo://CDS.VizieR/J/ApJ/886/93
- Title:
- SAMP. III. Opt. LCs and spectra of two AGNs
- Short Name:
- J/ApJ/886/93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Active galactic nuclei (AGNs) show a correlation between the size of the broad line region and the monochromatic continuum luminosity at 5100{AA}, allowing black hole mass estimation based on single-epoch spectra. However, the validity of the correlation is yet to be clearly tested for high-luminosity AGNs. We present the first reverberation mapping results of the Seoul National University AGN Monitoring Project (SAMP), which is designed to focus on luminous AGNs for probing the high end of the size-luminosity relation. We report time lag measurements of two AGNs, namely, 2MASSJ10261389+5237510 and SDSSJ161911.24+501109.2, using the light curves obtained over an ~1000d period with an average cadence of 10 and 20d, respectively, for photometry and spectroscopy monitoring. Based on a cross-correlation analysis and H{beta} line width measurements, we determine the H{beta} lag as 41.8_-6.0_^+4.9^ and 52.6_-14.7_^+17.6^ days in the observed frame, and black hole mass as 3.65_-0.57_^+0.49^x10^7^M_{sun}_ and 23.02_-6.56_^+7.81^x10^7^M_{sun}_, respectively, for 2MASS J1026 and SDSS J1619.
- ID:
- ivo://CDS.VizieR/J/MNRAS/452/2553
- Title:
- Sample of foreground-background quasar pairs
- Short Name:
- J/MNRAS/452/2553
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Previous observations of quasar host haloes at z~2 have uncovered large quantities of cool gas that exceed what is found around inactive galaxies of both lower and higher masses. To better understand the source of this excess cool gas, we compiled an exhaustive sample of 195 quasars at z~1 with constraints on chemically enriched, cool gas traced by MgII absorption in background quasar spectra from the Sloan Digital Sky Survey. This quasar sample spans a broad range of luminosities from L_bol_=10^44.4^ to 10^46.8^erg/s and allows an investigation of whether halo gas properties are connected with quasar properties. We find a strong correlation between luminosity and cool gas covering fraction. In particular, low-luminosity quasars exhibit a mean gas covering fraction comparable to inactive galaxies of similar masses, but more luminous quasars exhibit excess cool gas approaching what is reported previously at z~2. Moreover, 30-40 percent of the MgII absorption occurs at radial velocities of |Delta_v_|>300km/s from the quasar, inconsistent with gas bound to a typical quasar host halo. The large velocity offsets and observed luminosity dependence of the cool gas near quasars can be explained if the gas arises from: (1) neighbouring haloes correlated through large-scale structure at Mpc scales, (2) feedback from luminous quasars or (3) debris from the mergers thought to trigger luminous quasars. The first of these scenarios is in tension with the lack of correlation between quasar luminosity and clustering while the latter two make distinct predictions that can be tested with additional observations.
- ID:
- ivo://CDS.VizieR/J/A+A/643/A80
- Title:
- sample of HeII-emitters abundances
- Short Name:
- J/A+A/643/A80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Star-forming galaxies with nebular HeII emission contain very energetic ionizing sources of radiation, which can be considered as analogs to the major contributors of the reionization of the Universe in early epochs. It is therefore of great importance to provide a reliable absolute scale for the equivalent effective temperature (T*) for these sources. We study a sample of local (z<0.2) star-forming galaxies showing optical nebular HeII emission using the so-called softness diagrams, involving emission lines of two elements in two consecutive stages of ionization (e.g., [SII]/[SIII] vs. [OII]/[OIII]). We use for the first time the HeI/HeII ratio in these diagrams in order to explore the higher range of T* expected in these objects, and to investigate the role of possible mechanisms driving the distribution of galaxy points in these diagrams. We build grids of photoionization models covering different black-body temperatures, model cluster atmospheres, and density-bounded geometries to explain the conditions observed in the sample. We verified that the use of the softness diagrams including the emission-line ratio HeI/HeII combined with black-body photoionization models can provide an absolute scale of T* for these objects. The application of a Bayesian-like code indicates T* in the range 50-80kK for the sample of galaxies, with a mean value higher than 60kK. The average of these high temperature values can only be reproduced using cluster model populations with nearly metal-free stars, although such ionizing sources cannot explain either the highest T* values, beyond 1{sigma}, or the dispersion observed in the softness diagrams. According to our photoionization models, most sample galaxies could be affected to some extent by ionizing photon leaking, presenting a mean photon absorption fraction of 26% or higher depending on the metallicity assumed for the ionizing cluster. The entire range of HeI/HeII, [SII]/[SIII], and [OII]/[OIII] ratios for these HeII-emitting galaxies is reproduced with our models, combining nearly metal-free ionizing clusters and photon leaking under different density-bounded conditions.
- ID:
- ivo://CDS.VizieR/J/AJ/139/1857
- Title:
- Sample of major galaxy pairs at z=0.08-0.38
- Short Name:
- J/AJ/139/1857
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measure the strength, frequency, and timescale of tidally triggered star formation at redshift z=0.08-0.38 in a spectroscopically complete sample of galaxy pairs drawn from the magnitude-limited redshift survey of 9825 Smithsonian Hectospec Lensing Survey galaxies with R<20.3. To examine the evidence for tidal triggering, we identify a volume-limited sample of major (|{Delta}M_R_|<1.75, corresponding to mass ratio >1/5) pair galaxies with M_R_<-20.8 in the redshift range z=0.08-0.31.
- ID:
- ivo://CDS.VizieR/J/A+A/577/A9
- Title:
- Sc, V, Mn, and Co in Milky Way stars
- Short Name:
- J/A+A/577/A9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the elemental abundances of a large sample of F and G dwarfs in the solar neighborhood. The analysis is based on high-resolution spectra obtained with MIKE on the Magellan telescope, FEROS on the ESO 1.5m and 2.2m telescopes, HARPS on the ESO 3.6m telescope, UVES on the ESO Very Large Telescope, SOFIN and FIES on the Nordic Optical Telescope. We focused our study on odd-Z iron-peak elements Sc, V, Mn and Co. Our results show that Sc, V, and Co present similar trend as the alpha elements and in Co case, this is true also when non-local thermodynamic equilibrium corrections (non-LTE, NLTE) are applied. On the contrary Mn is generally underabundant relative the Sun but when NLTE corrections are applied the trend is basically flat with [Mn/Fe]=0. Considering the age as selection criterion for thin and thick disk we did not find any difference for V, Co, and Mn LTE while for Sc and Mn NLTE a small difference seem to be present. Comparisons with the alpha-element Ti show flat trends for all the elements except Mn that present well separated [Mn/Ti]-[Ti/H] for thin and thick disk.
- ID:
- ivo://CDS.VizieR/J/A+A/561/A83
- Title:
- SDC13 infrared dark clouds spectra
- Short Name:
- J/A+A/561/A83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Formation of stars is now believed to be tightly linked to the dynamical evolution of interstellar filaments in which they form. In this paper we analyze the density structure and kinematics of a small network of infrared dark filaments, SDC13, observed in both dust continuum and molecular line emission with the IRAM 30m telescope. These observations reveal the presence of 18 compact sources amongst which the two most massive, MM1 and MM2, are located at the intersection point of the parsec-long filaments. The dense gas velocity and velocity dispersion observed along these filaments show smooth, strongly correlated, gradients. We discuss the origin of the SDC13 velocity field in the context of filament longitudinal collapse. We show that the collapse timescale of the SDC13 filaments (from 1Myr to 4Myr depending on the model parameters) is consistent with the presence of Class I sources in them, and argue that, on top of bringing more material to the centre of the system, collapse could generate additional kinematic support against local fragmentation, helping the formation of starless super-Jeans cores. SDC13 is composed of three Spitzer Dark Clouds from the Peretto & Fuller (2009, cat J/A+A/505/405) catalogue (SDC13.174-0.07, SDC13.158-0.073, SDC13.194-0.073).
- ID:
- ivo://CDS.VizieR/J/ApJ/657/738
- Title:
- SDF galaxies multi-photometry
- Short Name:
- J/ApJ/657/738
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- SDF (Subaru Deep Field) line-emitting galaxies in four narrow-band filters at low and intermediate redshifts are presented. Broadband colors, follow-up optical spectroscopy, and multiple NB filters are used to distinguish H{alpha}, [OII], and [OIII] emitters at z=0.07-1.47 to construct their LFs. These LFs are derived down to faint magnitudes, allowing for an accurate determination of the faint-end slope. With a large (N~200) sample for each redshift interval, a Schechter profile is fitted to each LF.
