- ID:
- ivo://CDS.VizieR/J/ApJ/760/L33
- Title:
- Photometry of the Ic supernova PTF12gzk
- Short Name:
- J/ApJ/760/L33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discovery and extensive early-time observations of the Type Ic supernova (SN) PTF12gzk. Our light curves show a rise of 0.8mag within 2.5hr. Power-law fits (f(t){prop.to}(t-t_0_)^n^) to these data constrain the explosion date to within one day. We cannot rule out a quadratic fireball model, but higher values of n are possible as well for larger areas in the fit parameter space. Our bolometric light curve and a dense spectral sequence are used to estimate the physical parameters of the exploding star and of the explosion. We show that the photometric evolution of PTF12gzk is slower than that of most SNe Ic. The high ejecta expansion velocities we measure (~30000km/s derived from line minima four days after explosion) are similar to the observed velocities of broad-lined SNe Ic associated with gamma-ray bursts (GRBs) rather than to normal SN Ic velocities. Yet, this SN does not show the persistent broad lines that are typical of broad-lined SNe Ic. The host-galaxy characteristics are also consistent with GRB-SN hosts, and not with normal SN Ic hosts. By comparison with the spectroscopically similar SN 2004aw, we suggest that the observed properties of PTF12gzk indicate an initial progenitor mass of 25-35M_{sun}_ and a large ((5-10)x10^51^erg) kinetic energy, the later being close to the regime of GRB-SN properties.
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- ID:
- ivo://CDS.VizieR/J/ApJ/880/120
- Title:
- Photometry of the tidal disruption event PS18kh
- Short Name:
- J/ApJ/880/120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discovery of PS18kh, a tidal disruption event discovered at the center of SDSS J075654.53+341543.6 (d~322Mpc) by the Pan-STARRS Survey for Transients. Our data set includes pre-discovery survey data from Pan-STARRS, the All-sky Automated Survey for Supernovae, and the Asteroid Terrestrial-impact Last Alert System as well as high-cadence, multiwavelength follow-up data from ground-based telescopes and Swift, spanning from 56 days before peak light until 75days after. The optical/UV emission from PS18kh is well-fit as a blackbody with temperatures ranging from T~12000K to T~25000K and it peaked at a luminosity of L~8.8x10^43^erg/s. PS18kh radiated E=(3.45+/-0.22)x10^50^erg over the period of observation, with (1.42+/-0.20)x10^50^erg being released during the rise to peak. Spectra of PS18kh show a changing, boxy/double-peaked H{alpha} emission feature, which becomes more prominent over time. We use models of non-axisymmetric accretion disks to describe the profile of the H{alpha} line and its evolution. We find that at early times the high accretion rate leads the disk to emit a wind which modifies the shape of the line profile and makes it bell-shaped. At late times, the wind becomes optically thin, allowing the non-axisymmetric perturbations to show up in the line profile. The line-emitting portion of the disk extends from r_in_~60r_g_ to an outer radius of r_out_~1400r_g_ and the perturbations can be represented either as an eccentricity in the outer rings of the disk or as a spiral arm in the inner disk.
- ID:
- ivo://CDS.VizieR/J/ApJ/844/46
- Title:
- Photometry of the transient event iPTF16fnl
- Short Name:
- J/ApJ/844/46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present ground-based and Swift observations of iPTF16fnl, a likely tidal disruption event (TDE) discovered by the intermediate Palomar Transient Factory (iPTF) survey at 66.6Mpc. The light curve of the object peaked at an absolute mag M_g_=-17.2. The maximum bolometric luminosity (from optical and UV) was L_p_~(1.0+/-0.15)x10^43^erg/s, an order of magnitude fainter than any other optical TDE discovered so far. The luminosity in the first 60 days is consistent with an exponential decay, with L{propto}e^-(t-t_0_)/{tau}^, where t_0_=57631.0 (MJD) and {tau}~15 days. The X-ray shows a marginal detection at L_X_=2.4_-1.1_^1.9^x10^39^erg/s (Swift X-ray Telescope). No radio counterpart was detected down to 3{sigma}, providing upper limits for monochromatic radio luminosities of {nu}L_{nu}_<2.3x10^36^erg/s and {nu}L_{nu}_<1.7x10^37^erg/s (Very Large Array, 6.1 and 22GHz). The blackbody temperature, obtained from combined Swift UV and optical photometry, shows a constant value of 19000K. The transient spectrum at peak is characterized by broad HeII and H{alpha} emission lines, with FWHMs of about 14000km/s and 10000km/s, respectively. HeI lines are also detected at {lambda}{lambda}5875 and 6678. The spectrum of the host is dominated by strong Balmer absorption lines, which are consistent with a post-starburst (E+A) galaxy with an age of ~650Myr and solar metallicity. The characteristics of iPTF16fnl make it an outlier on both luminosity and decay timescales, as compared to other optically selected TDEs. The discovery of such a faint optical event suggests a higher rate of tidal disruptions, as low-luminosity events may have gone unnoticed in previous searches.
- ID:
- ivo://CDS.VizieR/J/AJ/158/186
- Title:
- Photometry of 12 totally eclipsing W UMa stars
- Short Name:
- J/AJ/158/186
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric observations of 12 totally eclipsing W UMa binaries (NSVS 3325547, V646 Lac, V1320 Cas, V539 Dra, V816 Cep, NSVS 9045055, V1115 Cas, V902 Cep, V596 Peg, NSVS 1768818, V619 Peg, and NSVS 3198272) are presented. We found that the longer (in phase units) the flat eclipses are, the smaller the mass ratios (or the reciprocal values) are. The mass ratios of five targets turned out close to the lower-mass ratio limit. We found that the periods of V1115 Cas and V646 Lac increase, while that of V596 Peg decreases. Masses, radii, and luminosities of the target components were calculated by the light-curve solutions and Gaia distances. In order to perform more reliable statistical analysis of the results we added to the sample of 12 targets from this paper another 29 totally eclipsing W UMa stars studied by us earlier. As a result we found the following trends: (a) the radius and luminosity of the target components increase with their mass but the dependencies are different from those of main-sequence (MS) stars; (b) the temperatures of stellar components whose masses are above 1 M_{sun}_ tend to be lower than those of the corresponding MS stars, while the temperatures of stellar components whose masses are below 1 M_{sun}_ tend to be higher than those of the corresponding MS stars; (c) there is no relationship between the fillout factor and mass ratio; and (d) 11 of the 41 targets are of A subtype, 24 are of W subtype, and 6 systems are with equal-temperature components.
- ID:
- ivo://CDS.VizieR/J/ApJ/729/143
- Title:
- Photometry of type IIn SN 2008am
- Short Name:
- J/ApJ/729/143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present observations and interpretation of the Type IIn supernova SN 2008am discovered by the ROTSE Supernova Verification Project (RSVP). SN 2008am peaked at approximately -22.3mag at a redshift of z=0.2338, giving it a peak luminosity of ~3x10^44^erg/s and making it one of the most luminous supernovae ever observed. The host galaxy appears to be an SB1 of normal luminosity (M_r'_~-20) with metallicity Z~0.4Z_{sun}_. ROTSE upper limits and detections constrain the rise time to be ~34 days in the rest frame, significantly shorter than similar events, SN 2006gy and SN 2006tf. Photometric observations in the ultraviolet, optical, and infrared bands (J, H, Ks) constrain the spectral energy distribution evolution. We obtained six optical spectra of the supernova, five on the early decline from maximum light and a sixth nearly a year later plus a very late time spectrum (~2yr) of the host galaxy. The spectra of SN 2008am show strong Balmer-line and HeI5876 emission with intermediate widths (~25{AA}) in the first ~40 days after optical maximum.
- ID:
- ivo://CDS.VizieR/J/ApJ/756/173
- Title:
- Photometry of type IIn SNe 2005ip and 2006jd
- Short Name:
- J/ApJ/756/173
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an observational study of the Type IIn supernovae (SNe IIn) 2005ip and 2006jd. Broadband UV, optical, and near-IR photometry, and visual-wavelength spectroscopy of SN 2005ip complement and extend upon published observations to 6.5 years past discovery. Our observations of SN 2006jd extend from UV to mid-infrared wavelengths, and like SN 2005ip, are compared to reported X-ray measurements to understand the nature of the progenitor. Both objects display a number of similarities with the 1988Z-like subclass of SN IIn including (1) remarkably similar early- and late-phase optical spectra, (2) a variety of high-ionization coronal lines, (3) long-duration optical and near-IR emission, and (4) evidence of cold and warm dust components. However, diversity is apparent, including an unprecedented late-time r-band excess in SN 2006jd. The observed differences are attributed to differences between the mass-loss history of the progenitor stars. We conclude that the progenitor of SN 2006jd likely experienced a significant mass-loss event during its pre-SN evolution akin to the great 19th century eruption of {eta} Carinae. Contrarily, as advocated by Smith et al., the circumstellar environment of SN 2005ip is found to be more consistent with a clumpy wind progenitor.
- ID:
- ivo://CDS.VizieR/J/A+A/275/484
- Title:
- 1990-1992 Photometry of UU Her
- Short Name:
- J/A+A/275/484
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/276/345
- Title:
- Photometry of variable LQ Hya
- Short Name:
- J/A+A/276/345
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/ApJ/627/579
- Title:
- Photometry of variables in NGC 3370
- Short Name:
- J/ApJ/627/579
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report observations of two nearby Type Ia supernovae (SNe Ia) for which observations of Cepheid variables in the host galaxies have been obtained with the Hubble Space Telescope: SN 1994ae in NGC 3370 and SN 1998aq in NGC 3982. For NCG 3370, we used the Advanced Camera for Surveys to observe 64 Cepheids that yield a distance of 29 Mpc, the farthest direct measurement of Cepheids.
- ID:
- ivo://CDS.VizieR/J/ApJ/743/19
- Title:
- Photometry of variable star candidates in M31
- Short Name:
- J/ApJ/743/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometry in B, V (down to V~26mag) is presented for two 23'x23' fields of the Andromeda galaxy (M31) that were observed with the blue channel camera of the Large Binocular Telescope during the Science Demonstration Time. Each field covers an area of about 5.1x5.1kpc^2^ at the distance of M31 ({mu}_M31_~24.4mag), sampling, respectively, a northeast region close to the M31 giant stream (field S2) and an eastern portion of the halo in the direction of the galaxy minor axis (field H1). The stream field spans a region that includes Andromeda's disk and giant stream, and this is reflected in the complexity of the color-magnitude diagram of the field. One corner of the halo field also includes a portion of the giant stream. Even though these demonstration time data were obtained under non-optimal observing conditions, the B photometry, which was acquired in time-series mode, allowed us to identify 274 variable stars (among which 96 are bona fide and 31 are candidate RR Lyrae stars, 71 are Cepheids, and 16 are binary systems) by applying the image subtraction technique to the selected portions of the observed fields. Differential flux light curves were obtained for the vast majority of these variables. Our sample mainly includes pulsating stars that populate the instability strip from the Classical Cepheids down to the RR Lyrae stars, thus tracing the different stellar generations in these regions of M31 down to the horizontal branch of the oldest (t~10Gyr) component.
