- ID:
- ivo://CDS.VizieR/J/MNRAS/448/732
- Title:
- Type Ia SN environment within host galaxies
- Short Name:
- J/MNRAS/448/732
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present constraints on Type Ia supernovae (SNe Ia) progenitors through an analysis of the environments found at the explosion sites of 102 events within star-forming host galaxies. H{alpha} and Galaxy Evolution Explorer near-ultraviolet (UV) images are used to trace on-going and recent star formation (SF), while broad-band B, R, J, K imaging is also analysed. Using pixel statistics we find that SNe Ia show the lowest degree of association with H{alpha} emission of all supernova (SN) types. It is also found that they do not trace near-UV emission. As the latter traces SF on time-scales less than 100Myr, this rules out any extreme 'prompt' delay times as the dominant progenitor channel of SNe Ia. SNe Ia best trace the B-band light distribution of their host galaxies. This implies that the population within star-forming galaxies is dominated by relatively young progenitors. Splitting SNe by their (B-V) colours at maximum light, 'redder' events show a higher degree of association with HII regions and are found more centrally within hosts. We discuss possible explanations of this result in terms of line-of-sight extinction and progenitor effects. No evidence for correlations between SN stretch and environment properties is observed.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/132/1023
- Title:
- U-band dropouts in Hubble Ultra Deep Field
- Short Name:
- J/AJ/132/1023
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We combine data from the extremely deep Hubble Space Telescope U (F300W) image, obtained using WFPC2 as part of the parallel observations of the Hubble Ultra Deep Field campaign, with BVi images from the Great Observatories Origins Deep Survey to identify a sample of Lyman break galaxies in the redshift range 2.0<=z<=3.5. We use recent stellar population synthesis models with a wide variety of ages, metallicities, redshifts, and dust content, and a detailed representation of the HI cosmic opacity as a function of redshift to model the colors of galaxies in our combination of WFPC2 and ACS filters. Using these models, we derive improved color selection criteria that provide a clean selection of relatively unobscured star-forming galaxies in this redshift range. Our WFPC2 F300W image is the deepest image ever obtained at that wavelength. The 10 limiting magnitude measured over 0.2arcsec^2^ is 27.5mag in the WFPC2 F300W image, about 0.5mag deeper than the F300W image in the Hubble Deep Field (HDF)-North.
- ID:
- ivo://CDS.VizieR/J/ApJ/893/143
- Title:
- UBVRIJHK & spec. obs. of type Ia SN2019ein
- Short Name:
- J/ApJ/893/143
- Date:
- 07 Mar 2022 07:30:20
- Publisher:
- CDS
- Description:
- We present optical observations of the Type Ia supernova (SN) 2019ein, starting two days after the estimated explosion date. The spectra and light curves show that SN 2019ein belongs to a high-velocity (HV) and broad-line group with a relatively rapid decline in the light curves ({Delta}m_15_(B)=1.36+/-0.02mag) and a short rise time (15.37+/-0.55days). The SiII{lambda}6355 velocity, associated with a photospheric component but not with a detached high-velocity feature, reached ~20000km/s 12 days before the B-band maximum. The line velocity, however, decreased very rapidly and smoothly toward maximum light, to ~13000km/s, which is relatively low among HV SNe. This indicates that the speed of the spectral evolution of HV SNe Ia is correlated with not only the velocity at maximum light, but also the light-curve decline rate, as is the case for normal-velocity (NV) SNeIa. Spectral synthesis modeling shows that the outermost layer at >17000km/s is well described by an O-Ne-C burning layer extending to at least 25000km/s, and there is no unburnt carbon below 30000km/s; these properties are largely consistent with the delayed detonation scenario and are shared with the prototypical HV SN 2002bo despite the large difference in {Delta}m_15_(B). This structure is strikingly different from that derived for the well-studied NV SN 2011fe. We suggest that the relation between the mass of ^56^Ni (or {Delta}m_15_) and the extent of the O-Ne-C burning layer provides an important constraint on the explosion mechanism(s) of HV and NV SNe.
- ID:
- ivo://CDS.VizieR/J/A+AS/138/87
- Title:
- UBVRI photometry of EUV stellar sources
- Short Name:
- J/A+AS/138/87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of high-precision UBV(RI)_c_ photometric observations and of spectroscopic radial velocity measurements obtained at the European Southern Observatory for a sample of 51 cool stars detected in the EUV by the ROSAT Wide Field Camera (WFC). Using also recent results from HIPPARCOS, we infer spectral types and investigate the single or binary nature of the sample stars. Optical variability, with periods in the 0.4-13 day range, has been detected for the first time in 15 of these stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/923/257
- Title:
- Ultra-diffuse galaxies with spectroscopic obs.
- Short Name:
- J/ApJ/923/257
- Date:
- 14 Mar 2022 07:42:35
- Publisher:
- CDS
- Description:
- We present new redshift measurements for 19 candidate ultra-diffuse galaxies (UDGs) from the Systematically Measuring Ultra-Diffuse Galaxies (SMUDGes) survey after conducting a long-slit spectroscopic follow-up campaign on 23 candidates with the Large Binocular Telescope. We combine these results with redshift measurements from other sources for 29 SMUDGes and 20 non-SMUDGes candidate UDGs. Together, this sample yields 44 spectroscopically confirmed UDGs (r_e_>=1.5kpc and {mu}_g_(0)>=24mag/arcsec^2^ within uncertainties) and spans cluster and field environments, with all but one projected on the Coma cluster and environs. We find no statistically significant differences in the structural parameters of cluster and noncluster confirmed UDGs, although there are hints of differences among the axis ratio distributions. Similarly, we find no significant structural differences among those in locally dense or sparse environments. However, we observe a significant difference in color with respect to projected clustercentric radius, confirming trends observed previously in statistical UDG samples. This trend strengthens further when considering whether UDGs reside in either cluster or locally dense environments, suggesting starkly different star formation histories for UDGs residing in high- and low-density environments. Of the 16 large (r_e_>=3.5kpc) UDGs in our sample, only one is a field galaxy that falls near the early-type galaxy red sequence. No other field UDGs found in low-density environments fall near the red sequence. This finding, in combination with our detection of Galaxy Evolution Explorer NUV flux in nearly half of the UDGs in sparse environments, suggests that field UDGs are a population of slowly evolving galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/861/153
- Title:
- Ultraviolet Extinction in the GALEX Bands. UVEXT
- Short Name:
- J/ApJ/861/153
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Interstellar extinction in ultraviolet is the most severe in comparison with optical and infrared wavebands and a precise determination plays an important role in correctly recovering the ultraviolet brightness and colors of objects. By finding the observed bluest colors at the given effective temperature and metallicity range of dwarf stars, stellar intrinsic colors, C_B,V_^0^, C_NUV,B_^0^, C_FUV,B_^0^, and C_FUV,NUV_^0^, are derived according to the stellar parameters from the LAMOST spectroscopic survey and photometric results from the GALEX and APASS surveys. With the derived intrinsic colors, the ultraviolet color excesses are calculated for about 25,000 A- and F-type dwarf stars. Analysis of the color excess ratios yields the extinction law related to the GALEX UV bands: E_NUV,B_/E_B,V_=3.77, E_FUV,B_/E_B,V_=3.39, and E_FUV,NUV_/E_B,V_=-0.38. The results agree very well with previous works in the NUV band and in general with the extinction curve derived by Fitzpatrick (1999PASP..111...63F) for R_V_=3.35.
- ID:
- ivo://CDS.VizieR/J/ApJS/95/163
- Title:
- Ultraviolet P Cygni profiles
- Short Name:
- J/ApJS/95/163
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have selected spectra of 232 stars from the IUE archives for inclusion in an atlas intended for various uses but tailored especially for the study of stellar winds. The atlas covers the range in spectral types from O3 to F8. The full atlas covers the reduced and normalized high resolution spectra from the IUE long- and short-wavelength spectrographs. Here we discuss the selection of the stars and the data reduction, and we present in velocity units the profiles of lines formed in the stellar winds. The selected lines cover a wide range of ionizations, allowing a comparison of the profiles from different ions in the wind of each star and a comparison of the different wind lines as a function of spectral type and luminosity. We also present the basic data on the program stars to facilitate study of the dependence of wind features on stellar parameters such as luminosity, temperature, escape velocity, and v sin i. We provide an overview of the characteristic behavior of the wind lines in the H-R diagram. The complete spectra are available in digital form through the NASA Astrophysics Data System (ADS). We offer a description of the electronic database that is available through the ADS and guidelines for obtaining access to that database.
- ID:
- ivo://CDS.VizieR/J/AJ/137/3761
- Title:
- Ultraviolet quasi-stellar objects
- Short Name:
- J/AJ/137/3761
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of spectroscopically confirmed quasi-stellar objects (QSOs) with FUV-NUV color (as measured by Galaxy Evolution Explorer (GALEX) photometry, FUV band: 1344-1786{AA}, NUV band: 1771-2831{AA}) bluer than canonical QSO templates and than the majority of known QSOs. We analyze their FUV to NIR colors, luminosities, and optical spectra. The sample includes a group of 150 objects at low redshift (z<0.5), and a group of 21 objects with redshift 1.7<z<2.6.
- ID:
- ivo://CDS.VizieR/J/ApJS/171/249
- Title:
- Ultraviolet Spectral Atlas of VV Cephei
- Short Name:
- J/ApJS/171/249
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The first observations of the ultraviolet spectrum of the binary system VV Cep (M2Iab + B?) during total eclipse have been made with the HST. A rich emission-line spectrum is seen, with over two thousand emission features present. Shortward of 1600{AA}, a weak continuum presumably due to Rayleigh scattering of the hot component is present, strengthening markedly shortward of 1500{AA}. The continuum of the M supergiant becomes apparent longward of 2650{AA}. Numerous circumstellar and interstellar absorption features are also seen. We present an atlas of the spectrum from 1300-3160{AA} as observed near midtotality and at two epochs closer to egress, when gas surrounding the hot component has begun to emerge from eclipse and the flux on the short-wavelength edges of many emission lines has increased. This atlas has been annotated with line identifications. Circumstellar and interstellar absorption features seen out of eclipse remain in absorption during totality and are also annotated on the atlas. Well over 90% of the emission features have plausible identifications, but there are many blends. Only a few hundred features appear to be free enough from blending for useful measurement of the peak flux in the line. We present a list of these unblended features.
- ID:
- ivo://CDS.VizieR/J/A+AS/113/237
- Title:
- Ultraviolet Spectrum of the Sun
- Short Name:
- J/A+AS/113/237
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An ultraviolet atlas of the solar spectrum with a spectral resolution of 15mA in the region 1948-2000A is presented. It is the first part of the spectra recorded on the quiet Sun between 1900 and 2130A. Measurements were performed from a balloon-borne instrumentation flown at an altitude of 39km. The wavelength atlas with a list of about 550 lines has been synthesized from data at center of the Sun ({mu}=1) and at {mu}=0.89, smoothed out over an area of 30 arcsec. The wavelength scale is given with respect to the average solar spectrum. Tracings are presented at {mu}=0.89, with an intensity scale adjusted in absolute values on the level of the continuum near 2000A.
