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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/A+A/468/L13
- Title:
- Photometry of the trans-Neptunian object 2005FY9
- Short Name:
- J/A+A/468/L13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The goal of this work is the study of 2005FY_9's short term variability in order to determine the amplitude of the lightcurve, which can be linked to the degree of elongation of the body or to the degree of albedo heterogeneity on the surface. Besides, the rotation period can be determined. CCD photometric observations of the transneptunian object 2005FY_9 in R band on 21 nights spanning several months have been carried out using the 1.5m telescope at Sierra Nevada Observatory and the 2.2m telescope at Calar Alto Observatory. The time series analysis results in confident detection of short-term variability. The most significant periodicities are 11.24+/-0.01h and its double, but other possibilities cannot be ruled out. The 22.48h double peaked rotational phase curve is slightly preferred from our analysis. As for the amplitude of the lightcurve, we get a peak to peak variability of 0.03+/-0.01mag. This result is compatible with a nearly spherical body that has a very homogeneous surface. There is also the possibility that the body is rotating nearly pole on, but we believe this is less likely. Very weak constraints are obtained for the density and internal strength based on the rotational properties derived from the photometry.
- ID:
- ivo://CDS.VizieR/J/A+A/315/40
- Title:
- Photometry of the Tuc dwarf galaxy
- Short Name:
- J/A+A/315/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present V and I CCD photometry for ~360 stars in the recently discovered dwarf galaxy Tucana. The large field investigated and the accurate photometric calibration make our data complementary to the deeper HST photometry. From the I magnitude of the tip of the red giant branch we estimate a distance modulus (m-M)_0_=24.69+/-0.16, corresponding to 870+/-60Kpc, confirming that Tucana is an isolated dwarf spheroidal located almost at the border of the Local Group. From the color of the red giant branch tip and by direct comparison with the giant branches of galactic globular clusters we estimate a metallicity [Fe/H]=-1.8+/-0.2, with no clear indication for a metallicity spread. The color-magnitude diagram indicates that Tucana has had a single star formation burst at the epoch of the Galactic globular cluster star formation. There is no evidence for an intermediate or young stellar population. We derive the V luminosity profile, the surface density profile of resolved stars, and the structural parameters of Tucana, from which we confirm that Tucana participates to the general metallicity-surface brightness-absolute magnitude relations defined by the Galaxy and M31 dwarf spheroidal and dwarf elliptical companions.
- ID:
- ivo://CDS.VizieR/J/ApJ/821/57
- Title:
- Photometry of the Type Ib/c SN2013ge
- Short Name:
- J/ApJ/821/57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present extensive multiwavelength (radio to X-ray) observations of the Type Ib/c supernova (SN Ib/c) SN 2013ge from -13 to +457 days relative to maximum light, including a series of optical spectra and Swift UV-optical photometry beginning 2-4 days post-explosion. This data set makes SN 2013ge one of the best-observed normal SNe Ib/c at early times - when the light curve is particularly sensitive to the progenitor configuration and mixing of radioactive elements - and reveals two distinct light curve components in the UV bands.
- ID:
- ivo://CDS.VizieR/J/A+A/573/A95
- Title:
- Photometry of the young open cluster Pismis 24
- Short Name:
- J/A+A/573/A95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a study of the stellar population of the young open cluster Pismis 24 (RA~17:24:44, DE~-34:12). Observations were carried out through JHKs filters with SofI at NTT (ESO). Photometry in the IRAC (onboard satellite Spitzer) bands (3.6, 4.5, 5.8, and 8.0-micron) was performed on deep archive images. Optical photometry in the Cousins VI bands was performed on WFC2 (onboard the HST) archive images. High-resolution X-ray photometry with ACIS (onboard satellite Chandra) was taken from Wang et al. (2007). Source coordinates were obtained by matching SofI Ks sources to 2MASS K sources. Table 1 lists the sources retrieved in the SofI field (without VI photometry). Table 2 contains the subsample of sources from Table 1 falling in the smaller WFC2 field (including VI photometry).
- 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/AJ/133/665
- Title:
- Photometry of type II Cepheid candidates
- Short Name:
- J/AJ/133/665
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained VR photometry of 205 Cepheid variable star candidates that were discovered in a small section of the Northern Sky Variability Survey. Given their locations and apparent magnitudes, any stars in this sample that are Cepheids are very likely to be type II Cepheids. On the basis of the regularity of variation, revised periods, light-curve morphology, slope of the color-magnitude relation, and color, we have identified 97 probable Cepheids and 17 possible Cepheids. While some of the photometric properties, particularly the colors, are consistent with the identification of these stars as Cepheids, the amplitudes are small compared to known type II Cepheids and the period distribution does not match that of known type II Cepheids.
- ID:
- ivo://CDS.VizieR/J/AJ/129/2007
- Title:
- Photometry of type II Cepheids. II
- Short Name:
- J/AJ/129/2007
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 668 new photometric observations for 24 Cepheids with periods less than 3 days. Most of the stars are probable type II Cepheids, but we have included some type I Cepheids for comparison. A discussion of the Fourier parameters of the light curves leads to the conclusion that they can be used to distinguish among the several types of light curves found among the type II stars but are of limited usefulness for distinguishing between type I and type II Cepheids.
