- ID:
- ivo://CDS.VizieR/J/MNRAS/448/2608
- Title:
- UV and optical photometric data for SN 2013by
- Short Name:
- J/MNRAS/448/2608
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present multiband ultraviolet and optical light curves, as well as visual-wavelength and near-infrared spectroscopy of the Type II linear (IIL) supernova (SN) 2013by. We show that SN 2013by and other SNe IIL in the literature, after their linear decline phase that start after maximum, have a sharp light-curve decline similar to that seen in SNe IIP. This light-curve feature has rarely been observed in other SNe IIL due to their relative rarity and the intrinsic faintness of this particular phase of the light curve. We suggest that the presence of this drop could be used as a physical parameter to distinguish between subclasses of SNe II, rather than their light-curve decline rate shortly after peak. Close inspection of the spectra of SN 2013by indicate asymmetric line profiles and signatures of high-velocity hydrogen. Late (~90d after explosion) near-infrared spectra of SN 2013by exhibit oxygen lines, indicating significant mixing within the ejecta. From the late-time light curve, we estimate that 0.029 M_{sun}_ of ^56^Ni was synthesized during the explosion. It is also shown that the V-band light-curve slope is responsible for part of the scatter in the luminosity (V magnitude 50d after explosion) versus ^56^Ni relation. Our observations of SN 2013by and other SNe IIL through the onset of the nebular phase indicate that their progenitors are similar to those of SNe IIP.
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- ID:
- ivo://CDS.VizieR/J/AJ/126/1208
- Title:
- UVBI magnitudes and redshifts in HDF-South
- Short Name:
- J/AJ/126/1208
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 97 (*) spectroscopic redshifts of z<1 galaxies in the Hubble Deep Field South (HDF-S) and its flanking fields (FFs). In the HDF-S proper we observed approximately half the galaxies brighter than I_814_(AB)=24 and obtained redshifts for 76% of them. Targets in our HDF-S sample were preselected to be at z<1 based on photometric redshifts, while in the FFs a simple magnitude cut was used. The photometric redshift preselection in the HDF-S resulted in a spectroscopic success rate that is significantly higher than in the FFs, where no preselection was applied. The rms precision of our redshift measurements, determined from repeat observations, is {delta}z=0.0003. We present the photometry and redshifts for the 97 objects for which we secured spectroscopic redshifts and describe the basic properties of this sample. The photometry was derived from the HST observations; the spectroscopy was obtained at the VLT using the FORS2 spectrograph on the Kueyen (UT2) and Yepun (UT4) 8.2m telescopes. (*) Actually, 103 redshifts in table1.
- ID:
- ivo://CDS.VizieR/J/A+A/415/273
- Title:
- UVBRI photometry and spectroscopy of AG Dra
- Short Name:
- J/A+A/415/273
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric UBVri observations of the symbiotic star AG Dra in Piwnice Observatory, Torun, Poland, are presented in tables 2 and 3. The 60cm telescope and a single-channel photoelectric photometer have been used. Table 2 lists observations with the EMI9558B photomultiplier tube from March 1996 to September 1999. Table 3 lists observations with the cooled C31034 photomultiplier tube from October 2001 to May 2003. Table 4 lists equivalent widths (EW) of the four emission lines in the spectrum of AG Dra: The Raman scattered line at 6825{AA}, H{alpha}, H{beta} and He II 4686{AA}. The spectroscopic observations have been performed in Tartu Observatory, Estonia, using the 1.5m telescope and a Cassegrain spectrograph. The time interval extends from September 1997 to March 2003.
- ID:
- ivo://CDS.VizieR/J/A+AS/103/183
- Title:
- UVBRI photometry of FK Com
- Short Name:
- J/A+AS/103/183
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/ApJS/235/16
- Title:
- UV emission of stars in LAMOST. I. Catalogs
- Short Name:
- J/ApJS/235/16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the ultraviolet magnitudes for over three million stars in the LAMOST survey, in which 2,202,116 stars are detected by GALEX. For 889,235 undetected stars, we develop a method to estimate their upper limit magnitudes. The distribution of (FUV-NUV) shows that the color declines with increasing effective temperature for stars hotter than 7000K in our sample, while the trend disappears for the cooler stars due to upper atmosphere emission from the regions higher than their photospheres. For stars with valid stellar parameters, we calculate the UV excesses with synthetic model spectra, and find that the (FUV - NUV) versus R'_FUV_ can be fitted with a linear relation and late-type dwarfs tend to have high UV excesses. There are 87,178 and 1,498,103 stars detected more than once in the visit exposures of GALEX in the FUV and NUV, respectively. We make use of the quantified photometric errors to determine statistical properties of the UV variation, including intrinsic variability and the structure function on the timescale of days. The overall occurrence of possible false positives is below 1.3% in our sample. UV absolute magnitudes are calculated for stars with valid parallaxes, which could serve as a possible reference frame in the NUV. We conclude that the colors related to UV provide good criteria to distinguish between M giants and M dwarfs, and the variability of RR Lyrae stars in our sample is stronger than that of other A and F stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/406/420
- Title:
- UV/far-IR data of infrared excess sources
- Short Name:
- J/MNRAS/406/420
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We explore the nature of Infrared Excess sources (IRX), which are proposed as candidates for luminous [LX(2-10keV)>10^43^erg/s] Compton thick (NH>2x10^24^cm^-2^) QSOs at z~~2. Lower redshift, z~~1, analogues of the distant IRX population are identified by first redshifting to z=2 the spectral energy distributions (SEDs) of all sources with secure spectroscopic redshifts in the AEGIS (6488) and the GOODS-North (1784) surveys and then selecting those that qualify as IRX sources at that redshift. A total of 19 galaxies are selected. The mean redshift of the sample is z~~1. We do not find strong evidence for Compton thick QSOs in the sample. For nine sources with X-ray counterparts, the X-ray spectra are consistent with Compton thin active galactic nucleus (AGN). Only three of them show tentative evidence for Compton thick obscuration. The SEDs of the X-ray undetected population are consistent with starburst activity.
- ID:
- ivo://CDS.VizieR/J/ApJ/879/131
- Title:
- UV-FIR obs. of post-starburst galaxies & dust masses
- Short Name:
- J/ApJ/879/131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive dust masses (M_dust_) from the spectral energy distributions of 58 post-starburst galaxies (PSBs). There is an anticorrelation between specific dust mass (M_dust_/M_*_) and the time elapsed since the starburst ended, indicating that dust was either destroyed, expelled, or rendered undetectable over the ~1Gyr after the burst. The M_dust_/M_*_ depletion timescale, 205_-37_^+58^Myr, is consistent with that of the CO-traced M_H2_/M_*_, suggesting that dust and gas are altered via the same process. Extrapolating these trends leads to the M_dust_/M_*_ and M_H2_/M_*_ values of early-type galaxies (ETGs) within 1-2Gyr, a timescale consistent with the evolution of other PSB properties into ETGs. Comparing Mdust and M_H2_ for PSBs yields a calibration, log M_H2_=0.45logM_dust_+6.02, that allows us to place 33 PSBs on the Kennicutt-Schmidt (KS) plane, {Sigma}SFR-{Sigma}M_H2_. Over the first ~200-300Myr, the PSBs evolve down and off of the KS relation, as their star formation rate (SFR) decreases more rapidly than M_H2_. Afterwards, M_H2_ continues to decline whereas the SFR levels off. These trends suggest that the star formation efficiency bottoms out at 10^-11^/yr and will rise to ETG levels within 0.5-1.1Gyr afterwards. The SFR decline after the burst is likely due to the absence of gas denser than the CO-traced H2. The mechanism of the M_dust_/M_*_ and M_H2_/M_*_ decline, whose timescale suggests active galactic nucleus/low-ionization nuclear emission-line region feedback, may also be preventing the large CO-traced molecular gas reservoirs from collapsing and forming denser star-forming clouds.
- ID:
- ivo://CDS.VizieR/J/ApJ/771/13
- Title:
- UV-IR photometry of SMC stars
- Short Name:
- J/ApJ/771/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The nature of the progenitors of Type Ia supernovae (SNe Ia) is still a mystery. While plausible candidates are known for both the single-degenerate and double-degenerate models, the observed numbers fall significantly short of what is required to reproduce the SNe Ia rate. Some of the most promising single-degenerate Type Ia progenitors are recurrent novae and super-soft sources (SSS). White dwarfs (WDs) with higher mass transfer rates can also be SN Ia progenitors. For these rapidly accreting white dwarfs (RAWDs), more material than is needed for steady burning accretes on the WD, and extends the WD's photosphere. Unlike SSS, such objects will likely not be detectable at soft X-ray energies, but will be bright at longer wavelengths, such as the far-ultraviolet (UV). Possible examples include LMC N66 and the V Sagittae stars. We present a survey using multi-object spectrographs looking for RAWDs in the central core of the Small Magellanic Cloud (SMC), from objects selected to be bright in the far-UV and with blue far UV-V colors. While we find some unusual objects, and recover known planetary nebula and Wolf-Rayet (WR) stars, we detect no candidate RAWD. The upper limits from this non-detection depend on our expectations of what an RAWD should look like, as well assumptions about the internal extinction of the SMC. Assuming they resemble LMC N66 or fainter versions of WR stars we set an upper limit of 10-14 RAWDs in the SMC. However, our survey is unlikely to detect objects like V Sge, and hence we cannot set meaningful upper limits if RAWDs generally resemble V Sge.
- ID:
- ivo://CDS.VizieR/J/ApJ/883/147
- Title:
- UV-NIR LCs of the energetic H-stripped SN2016coi
- Short Name:
- J/ApJ/883/147
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present comprehensive observations and analysis of the energetic H-stripped SN 2016coi (a.k.a. ASASSN-16fp), spanning the {gamma}-ray through optical and radio wavelengths, acquired within the first hours to ~420 days post explosion. Our observational campaign confirms the identification of He in the supernova (SN) ejecta, which we interpret to be caused by a larger mixing of Ni into the outer ejecta layers. By modeling the broad bolometric light curve, we derive a large ejecta-mass-to-kinetic-energy ratio (M_ej_~4-7M_{sun}_, E_k_~(7-8)x10^51^erg). The small [CaII]{lambda}{lambda}7291,7324 to [OI]{lambda}{lambda}6300,6364 ratio (~0.2) observed in our late-time optical spectra is suggestive of a large progenitor core mass at the time of collapse. We find that SN 2016coi is a luminous source of X-rays (L_X_>10^39^erg/s in the first ~100 days post explosion) and radio emission (L_8.5GHz_~7x10^27^erg/s/Hz at peak). These values are in line with those of relativistic SNe (2009bb, 2012ap). However, for SN 2016coi, we infer substantial pre-explosion progenitor mass loss with a rate dM/dt~(1-2)x10^-4^M_{sun}_/yr and a sub-relativistic shock velocity v_sh_~0.15c, which is in stark contrast with relativistic SNe and similar to normal SNe. Finally, we find no evidence for a SN- associated shock breakout {gamma}-ray pulse with energy E_{gamma}_>2x10^46^erg. While we cannot exclude the presence of a companion in a binary system, taken together, our findings are consistent with a massive single-star progenitor that experienced large mass loss in the years leading up to core collapse, but was unable to achieve complete stripping of its outer layers before explosion.
- ID:
- ivo://CDS.VizieR/J/ApJ/892/93
- Title:
- UV-NIR monitoring campaign of NGC 4395
- Short Name:
- J/ApJ/892/93
- Date:
- 19 Jan 2022 09:00:14
- Publisher:
- CDS
- Description:
- We present a variability study of the lowest-luminosity Seyfert 1 nucleus of the galaxy NGC 4395 based on photometric monitoring campaigns in 2017 and 2018. Using 22 ground-based and space telescopes, we monitored NGC 4395 with a ~5-minute cadence during a period of 10 days and obtained light curves in the ultraviolet (UV), V, J, H, and K/K_s_ bands, as well as narrowband H{alpha}. The rms variability is ~0.13mag in the Swift UVM2 and V filter light curves, decreasing down to ~0.01mag in the K filter. After correcting for the continuum contribution to the H{alpha} narrow band, we measured the time lag of the H{alpha} emission line with respect to the V-band continuum as 55_-31_^+27^-122_-67_^+33^min in 2017 and 49_-14_^+15^-83_-14_^+13^min in 2018, depending on assumptions about the continuum variability amplitude in the H{alpha} narrow band. We obtained no reliable measurements for the continuum-to-continuum lag between UV and V bands and among near-IR bands, owing to the large flux uncertainty of UV observations and the limited time baseline. We determined the active galactic nucleus (AGN) monochromatic luminosity at 5100{AA}, {lambda}L_{lambda}_=(5.75+/-0.40)x10^39^erg/s, after subtracting the contribution of the nuclear star cluster. While the optical luminosity of NGC 4395 is two orders of magnitude lower than that of other reverberation-mapped AGNs, NGC 4395 follows the size-luminosity relation, albeit with an offset of 0.48dex (>=2.5{sigma}) from the previous best-fit relation of Bentz+ 2013ApJ...767..149B
