- ID:
- ivo://CDS.VizieR/J/MNRAS/426/1972
- Title:
- H_2_O Southern Galactic Plane Survey, HOPS. II
- Short Name:
- J/MNRAS/426/1972
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The H2O Southern Galactic Plane Survey (HOPS) has mapped a 100{deg} strip of the Galactic plane (-70{deg}>l>30{deg}, |b|<0.5{deg}) using the 22m Mopra antenna at 12mm wavelengths. Observations were conducted in on-the-fly mode using the Mopra spectrometer (MOPS), targeting water masers, thermal molecular emission and radio-recombination lines. Foremost among the thermal lines are the 23GHz transitions of NH3 J,K=(1,1) and (2,2), which trace the densest parts of molecular clouds (n>10^4^cm^-3^). In this paper, we present the NH_3_(1,1) and (2,2) data, which have a resolution of 2arcmin and cover a velocity range of +/-200km/s.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/572/A21
- Title:
- H_2_O spectra of 29 nearby Class 0/I protostars
- Short Name:
- J/A+A/572/A21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Outflows are an important part of the star formation process as both the result of ongoing active accretion and one of the main sources of mechanical feedback on small scales. Water is the ideal tracer of these effects because it is present in high abundance for the conditions expected in various parts of the protostar, particularly the outflow. We constrain and quantify the physical conditions probed by water in the outflow-jet system for Class 0 and I sources. We present velocity-resolved Herschel HIFI spectra of multiple water-transitions observed towards 29 nearby Class 0/I protostars as part of the WISH guaranteed time key programme. The lines are decomposed into different Gaussian components, with each component related to one of three parts of the protostellar system; quiescent envelope, cavity shock and spot shocks in the jet and at the base of the outflow. We then use non-LTE radex models to constrain the excitation conditions present in the two outflow-related components.
- ID:
- ivo://CDS.VizieR/J/ApJ/685/235
- Title:
- Host and companion galaxies in the SDSS
- Short Name:
- J/ApJ/685/235
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measure the number of companions per galaxy (N_c_) as a function of r-band absolute magnitude for both the Sloan Digital Sky Survey (DR5) and the Croton and coworkers semianalytic catalog, 2006MNRAS.365...11C, applied to the Millennium Run simulation (Springel et al., 2005Natur.435..629S). For close pairs with projected separations of 5-20kpc/h, velocity differences less than 500km/s, and luminosity ratios between 1:2 and 2:1, we find good agreement between the observations and simulations, with N_c_ consistently close to 0.02 over the range -22<M_r_<-18. For larger pair separations, N_c_(M_r_) instead becomes increasingly steep toward the faint end, implying that luminosity-dependent clustering plays an important role on small scales. Using the simulations to assess and correct for projection effects, we infer that the real-space N_c_(M_r_) for close pairs peaks at about M^*^ and declines by at least a factor of 2 as M_r_ becomes fainter. Conversely, by measuring the number density of close companions, we estimate that at least 90% of all major mergers occur between galaxies which are fainter than L^*^. Finally, measurements of the luminosity density of close companions indicate that L^*^ galaxies likely dominate in terms of the overall importance of major mergers in the evolution of galaxy populations at low redshift.
- ID:
- ivo://CDS.VizieR/J/AJ/126/63
- Title:
- Host galaxies of 2MASS-QSOs with z<=3
- Short Name:
- J/AJ/126/63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present and discuss optical imaging of 76 active galactic nuclei (AGNs) that represent the selected Two Micron All Sky Survey (2MASS) sample for z<0.3, from a full list of 243. They are found to have dust-obscured nuclei, residing in host galaxies that show a high fraction (greater than 70%) of tidal interactions. The derived luminosities of the AGNs and host galaxies are similar to traditionally selected AGNs, and they may comprise some 40% of the total AGN population at low redshift. We have measured a number of host galaxy properties and discuss their distributions and interrelations. We compare the 2MASS AGNs with optically selected samples and the IRAS-selected galaxy samples and discuss the differences in terms of merger processes and initial conditions.
- ID:
- ivo://CDS.VizieR/J/ApJ/473/713
- Title:
- Host galaxies of powerful radio sources
- Short Name:
- J/ApJ/473/713
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper describes those properties of the host galaxies of powerful radio sources that are unique to radio galaxies. The radio galaxies have redshifts up to z=0.5 and radio powers, P(408MHz), ranging from 10^25^ to 10^28^W.Hz^-1^ (H_0_=50km.s^-1^.Mpc^-1^ and q_0_=0). We find that the magnitudes, colors, and surface brightness profiles of these radio galaxies are very diverse. Their rest frame V magnitudes range from -24th to -20th magnitude and are 0.55+/-0.06mag fainter than those of brightest cluster members. Their (B-V) colors can be as red as those of brightest cluster members but may also be ~1 mag bluer. The optical structure of the low-redshift (0.03<z<0.25) radio galaxies may vary ranging from cD to N galaxy behaviour. Although the host galaxies of the low-redshift radio sources are generally "elliptical-like" galaxies, a comparison of the overall structure of radio galaxies to those of radio- quiet "generalized elliptical galaxies" of Schombert shows that only 17% are genuine elliptical galaxies, 9% have elliptical profiles with truncated halos, 26% are roughly elliptical but have disturbed surface brightness profiles, 16% are cD or D galaxies, 7% have double nuclei, and 21% are N galaxies. The only property that radio galaxies, as a class, have in common is that their sizes are relatively larger than those of normal elliptical galaxies of the same absolute magnitude. At the 22d isophote (in V) radio galaxies are 11% larger, at the 24th isophote they are 15% larger, and at the 25th isophote they are 20% larger. The host galaxies of the low-redshift (0.03<z<0.25) FR I and FR II sources have different properties. 69% of all FR I's are associated with cD-like or double nucleus galaxies, 19% with smooth ellipticals, and 13% with disturbed ellipticals; no FR I's are associated with N galaxies. 41% of all FR IIs are associated with N galaxies, 26% with smooth ellipticals, and 26% with disturbed ellipticals; no FR II's are associated with cD-like galaxies. The colors and color gradients are also different, with the FR II's having both bluer colors and a larger dispersion in their color gradients. Powerful FR I and FR II sources exhibit differing cosmological evolutions in their number counts. At low redshifts, almost all powerful sources are FR I's, and at high redshifts they are predominantly FR II's. We suggest that powerful FR I's prefer host galaxies that are the dominant central galaxies of relaxed groups and clusters, while FR II's are most often associated with violent galaxy encounters.
- ID:
- ivo://CDS.VizieR/J/ApJ/722/566
- Title:
- Host galaxies of SNe Ia in SDSS-II SN survey
- Short Name:
- J/ApJ/722/566
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the host galaxy dependences of Type Ia Supernovae (SNe Ia) from the full three year sample of the SDSS-II Supernova Survey. We re-discover, to high significance, the strong correlation between host galaxy type and the width of the observed SN light curve, i.e., fainter, quickly declining SNe Ia favor passive host galaxies, while brighter, slowly declining Ia's favor star-forming galaxies. We also find evidence (at between 2{sigma} and 3{sigma}) that SNe Ia are ~0.1+/-0.04mag brighter in passive host galaxies than in star-forming hosts, after the SN Ia light curves have been standardized using the light-curve shape and color variations. This difference in brightness is present in both the SALT2 and MCLS2k2 light-curve fitting methodologies. We see evidence for differences in the SN Ia color relationship between passive and star-forming host galaxies, e.g., for the MLCS2k2 technique, we see that SNe Ia in passive hosts favor a dust law of R_V_=1.0+/-0.2, while SNe Ia in star-forming hosts require R_V_=1.8^+0.2^_-0.4_. The significance of these trends depends on the range of SN colors considered. We demonstrate that these effects can be parameterized using the stellar mass of the host galaxy (with a confidence of >4{sigma}) and including this extra parameter provides a better statistical fit to our data. Our results suggest that future cosmological analyses of SN Ia samples should include host galaxy information.
- ID:
- ivo://CDS.VizieR/J/ApJ/770/107
- Title:
- Host galaxies of SNIa from SNfactory
- Short Name:
- J/ApJ/770/107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometric and spectroscopic observations of galaxies hosting Type Ia supernovae (SNe Ia) observed by the Nearby Supernova Factory. Combining Galaxy Evolution Explorer (GALEX) UV data with optical and near-infrared photometry, we employ stellar population synthesis techniques to measure SN Ia host galaxy stellar masses, star formation rates (SFRs), and reddening due to dust. We reinforce the key role of GALEX UV data in deriving accurate estimates of galaxy SFRs and dust extinction. Optical spectra of SN Ia host galaxies are fitted simultaneously for their stellar continua and emission lines fluxes, from which we derive high-precision redshifts, gas-phase metallicities, and H{alpha}-based SFRs. With these data we show that SN Ia host galaxies present tight agreement with the fiducial galaxy mass-metallicity relation from Sloan Digital Sky Survey (SDSS) for stellar masses log(M_*_/M_{sun}_)>8.5 where the relation is well defined. The star formation activity of SN Ia host galaxies is consistent with a sample of comparable SDSS field galaxies, though this comparison is limited by systematic uncertainties in SFR measurements. Our analysis indicates that SN Ia host galaxies are, on average, typical representatives of normal field galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/458/84
- Title:
- Host galaxies of Superluminous Supernovae
- Short Name:
- J/MNRAS/458/84
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Hubble Space Telescope (HST) Wide Field Camera 3 UV and near-IR (nIR) imaging of 21 Superluminous Supernovae (SLSNe) host galaxies, providing a sensitive probe of star formation and stellar mass within the hosts. Comparing the photometric and morphological properties of these host galaxies with those of core-collapse supernovae (CCSNe) and long-duration gamma-ray bursts (LGRBs), we find SLSN hosts are fainter and more compact at both UV and nIR wavelengths, in some cases we barely recover hosts with absolute magnitude around M_V_~=-14. With the addition of ground based optical observations and archival results, we produce spectral energy distribution fits to these hosts, and show that SLSN hosts possess lower stellar mass and star formation rates. This is most pronounced for the hydrogen deficient Type-I SLSN hosts, although Type-II H-rich SLSN host galaxies remain distinct from the bulk of CCSNe, spanning a remarkably broad range of absolute magnitudes, with ~30 per cent of SLSNe-II arising from galaxies fainter than M_nIR_~-14. The detection of our faintest SLSN hosts increases the confidence that SLSNe-I hosts are distinct from those of LGRBs in star formation rate and stellar mass, and suggests that apparent similarities in metallicity may be due to the limited fraction of hosts for which emission line metallicity measurements are feasible. The broad range of luminosities of SLSN-II hosts is difficult to describe by metallicity cuts, and does not match the expectations of any reasonable UV-weighted luminosity function, suggesting additional environmental constraints are likely necessary to yield hydrogen rich SLSNe.
- ID:
- ivo://CDS.VizieR/J/MNRAS/438/1391
- Title:
- Host galaxies of Type Ia SN from PTF
- Short Name:
- J/MNRAS/438/1391
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectroscopic observations of the host galaxies of 82 low-redshift Type Ia supernovae (SNe Ia) discovered by the Palomar Transient Factory. We determine star formation rates, gas-phase/stellar metallicities, and stellar masses and ages of these objects. As expected, strong correlations between the SN Ia light-curve width (stretch) and the host age/mass/metallicity are found: fainter, faster declining events tend to be hosted by older/massive/metal-rich galaxies. There is some evidence that redder SNe Ia explode in higher metallicity galaxies, but we found no relation between the SN colour and host galaxy extinction based on the Balmer decrement, suggesting that the colour variation of these SNe does not primarily arise from this source. SNe Ia in higher mass/metallicity galaxies also appear brighter after stretch/colour corrections than their counterparts in lower mass hosts, and the stronger correlation is with gas-phase metallicity suggesting this may be the more important variable. We also compared the host stellar mass distribution to that in galaxy-targeted SN surveys and the high-redshift untargeted Supernova Legacy Survey (SNLS). SNLS has many more low-mass galaxies, while the targeted searches have fewer. This can be explained by an evolution in the galaxy stellar mass function, coupled with an SN delay-time distribution proportional to t^-1^. Finally, we found no significant difference in the mass-metallicity relation of our SN Ia hosts compared to field galaxies, suggesting any metallicity effect on the SN Ia rate is small.
- ID:
- ivo://CDS.VizieR/J/ApJ/830/13
- Title:
- Host-galaxy NUV-NIR data of 32 superluminous SNe
- Short Name:
- J/ApJ/830/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present ultraviolet through near-infrared photometry and spectroscopy of the host galaxies of all superluminous supernovae (SLSNe) discovered by the Palomar Transient Factory prior to 2013 and derive measurements of their luminosities, star formation rates, stellar masses, and gas-phase metallicities. We find that Type I (hydrogen-poor) SLSNe (SLSNe I) are found almost exclusively in low-mass (M_*_<2x10^9^M_{sun}_) and metal-poor (12+log_10_[O/H]<8.4) galaxies. We compare the mass and metallicity distributions of our sample to nearby galaxy catalogs in detail and conclude that the rate of SLSNe I as a fraction of all SNe is heavily suppressed in galaxies with metallicities >~0.5Z_{sun}_. Extremely low metallicities are not required and indeed provide no further increase in the relative SLSN rate. Several SLSN I hosts are undergoing vigorous starbursts, but this may simply be a side effect of metallicity dependence: dwarf galaxies tend to have bursty star formation histories. Type II (hydrogen-rich) SLSNe (SLSNe II) are found over the entire range of galaxy masses and metallicities, and their integrated properties do not suggest a strong preference for (or against) low-mass/low-metallicity galaxies. Two hosts exhibit unusual properties: PTF 10uhf is an SLSN I in a massive, luminous infrared galaxy at redshift z=0.29, while PTF 10tpz is an SLSN II located in the nucleus of an early-type host at z=0.04.