- ID:
- ivo://CDS.VizieR/J/A+A/654/A157
- Title:
- 5 ILRTs light curves and spectra
- Short Name:
- J/A+A/654/A157
- Date:
- 07 Mar 2022 07:10:34
- Publisher:
- CDS
- Description:
- We present the spectroscopic and photometric study of five intermediate-luminosity red transients (ILRTs), namely AT 2010dn, AT 2012jc, AT 2013la, AT 2013lb, and AT 2018aes. They share common observational properties and belong to a family of objects similar to the prototypical ILRT SN 2008S. These events have a rise time that is less than 15 days and absolute peak magnitudes of between -11:5 and -14:5mag. Their pseudo-bolometric light curves peak in the range 0.5-9.0*10^40^erg/s and their total radiated energies are on the order of (0.3-3)*10^47^erg. After maximum brightness, the light curves show a monotonic decline or a plateau, resembling those of faint supernovae IIL or IIP, respectively. At late phases, the light curves flatten, roughly following the slope of the ^56^Co decay. If the late-time power source is indeed radioactive decay, these transients produce ^56^Ni masses on the order of 10^-4^ to 10^-3^M_{sun}_. The spectral energy distribution of our ILRT sample, extending from the optical to the mid-infrared (MIR) domain, reveals a clear IR excess soon after explosion and non-negligible MIR emission at very late phases. The spectra show prominent H lines in emission with a typical velocity of a few hundred km/s, along with CaII features. In particular, the [CaII]7291,7324 doublet is visible at all times, which is a characteristic feature for this family of transients. The identified progenitor of SN 2008S, which is luminous in archival Spitzer MIR images, suggests an intermediate-mass precursor star embedded in a dusty cocoon. We propose the explosion of a super-asymptotic giant branch star forming an electron-capture supernova as a plausible explanation for these events.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/531/L2
- Title:
- Images of Vega at 1.3mm
- Short Name:
- J/A+A/531/L2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Previous studies have found that Vega is surrounded by an extended debris disc that is very smooth in the far infrared, but displays possible clumpiness at 850um and dust emission peaks at 1.3mm. We reobserved Vega at 1.3mm with PdBI to constrain its circumstellar dust distribution.
- ID:
- ivo://CDS.VizieR/J/A+A/343/841
- Title:
- Imaging of symbiotic stars
- Short Name:
- J/A+A/343/841
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Narrowband images of 51 symbiotic stars were obtained at the ESO and ORM observatories to search for resolved optical nebulae. Ionized nebulae much larger than previously known are found around CH Cyg, HM Sge and V1016 Cyg, and they will be discussed in detail in forthcoming papers. A nebula with a deconvolved size between 0.9" and 1.5" is found around the symbiotic Mira H 1-36. The radio sources located few arcminutes aside of R Aqr (Hollis et al., 1987ApJ...321L..55H), which were suggested to be the remnant of a prehistoric eruption of the system, are found to be background galaxies. We also present a bibliographical compilation, updated to October 1998, of all the extended nebulae around symbiotic stars detected at optical and radio wavelengths, as well as a list of optical non-detections. The statistics of occurrence of these large ionized nebulae among symbiotic stars is discussed. Extended ionized nebulae appear to be a common component of the D-type symbiotics, and we infer that they are formed by the Mira wind and/or high velocity winds ejected by the hot component during outbursts. On the contrary, very few nebulae are detected around the systems containing normal red giants.
- ID:
- ivo://CDS.VizieR/J/ApJ/842/42
- Title:
- Improved reddenings for 59 Galactic Cepheids
- Short Name:
- J/ApJ/842/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new photometric method by which improved high-precision reddenings and true distance moduli can be determined to individual Galactic Cepheids once distance measurements are available. We illustrate that the relative positioning of stars in the Cepheid period-luminosity (PL) relation (Leavitt law) is preserved as a function of wavelength. This information then provides a powerful constraint for determining reddenings to individual Cepheids, as well as their distances. As a first step, we apply this method to the 59 Cepheids in the compilation of Fouque et al. Updated reddenings, distance moduli (or parallaxes), and absolute magnitudes in seven (optical through near-infrared) bands are given. From these intrinsic quantities, multiwavelength PL and color-color relations are derived. We find that the V-band period-luminosity-color relation has an rms scatter of only 0.06mag, so that individual Cepheid distances can be measured to 3%, compared with dispersions of 6 to 13% for the one-parameter K through B PL relations, respectively. This method will be especially useful in conjunction with the new accurate parallax sample upcoming from Gaia.
- ID:
- ivo://CDS.VizieR/J/AJ/131/612
- Title:
- Infrared-optical phase lags in AGB stars
- Short Name:
- J/AJ/131/612
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To search for phase lags in the optical-infrared light curves of asymptotic giant branch stars, we have compared infrared data from the COBE DIRBE satellite with optical light curves from the AAVSO and other sources. We found 17 examples of phase lags between the times of infrared and optical maximum, and 4 stars with no observed lags.
- ID:
- ivo://CDS.VizieR/J/AJ/153/35
- Title:
- Infrared spectroscopy of symbiotic stars. XI.
- Short Name:
- J/AJ/153/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Employing new infrared radial velocities, we have computed spectroscopic orbits of the cool giants in four southern S-type symbiotic systems. The orbits for two of the systems, Hen 3-461 and Hen 3-828, have been determined for the first time, while orbits of the other two, SY Mus and AR Pav, have previously been determined. For the latter two systems, we compare our results with those in the literature. The low mass of the secondary of SY Mus suggests that it has gone through a common envelope phase. Hen 3-461 has an orbital period of 2271 days, one of the longest currently known for S-type symbiotic systems. That period is very different from the orbital period proposed previously from its photometric variations. The other three binaries have periods between 600 and 700 day, values that are typical for S-type symbiotic orbits. Basic properties of the M giant components and the distance to each system are determined.
- ID:
- ivo://CDS.VizieR/J/AJ/160/201
- Title:
- Infrared transmission spectrum for Kepler-79d
- Short Name:
- J/AJ/160/201
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Extremely low-density planets ("super-puffs") are a small but intriguing subset of the transiting planet population. With masses in the super-Earth range (1-10M{Earth}) and radii akin to those of giant planets (>4R{Earth}), their large envelopes may have been accreted beyond the water snow line and many appear to be susceptible to catastrophic mass loss. Both the presence of water and the importance of mass loss can be explored using transmission spectroscopy. Here, we present new Hubble space telescope WFC3 spectroscopy and updated Kepler transit depth measurements for the super-puff Kepler-79d. We do not detect any molecular absorption features in the 1.1-1.7{mu}m WFC3 bandpass, and the combined Kepler and WFC3 data are consistent with a flat-line model, indicating the presence of aerosols in the atmosphere. We compare the shape of Kepler-79d transmission spectrum to predictions from a microphysical haze model that incorporates an outward particle flux due to ongoing mass loss. We find that photochemical hazes offer an attractive explanation for the observed properties of super-puffs like Kepler-79d, as they simultaneously render the near-infrared spectrum featureless and reduce the inferred envelope mass-loss rate by moving the measured radius (optical depth unity surface during transit) to lower pressures. We revisit the broader question of mass-loss rates for super-puffs and find that the age estimates and mass-loss rates for the majority of super-puffs can be reconciled if hazes move the photosphere from the typically assumed pressure of ~10mbar to ~10{mu}bar.
- ID:
- ivo://CDS.VizieR/J/ApJ/715/277
- Title:
- Insights into the Cepheid distance scale
- Short Name:
- J/ApJ/715/277
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed investigation of the Cepheid distance scale by using both theory and observations. Through the use of pulsation models for fundamental mode Cepheids, we found that the slope of the period-luminosity (P-L) relation covering the entire period range (0.40<=logP<=2.0) becomes steeper when moving from optical to near-infrared (NIR) bands, and that the metallicity dependence of the slope decreases from the B- to the K band. The sign of the metallicity dependence for the slopes of the P-LV and P-LI relation is at odds with some recent empirical estimates. We determined new homogeneous estimates of V- and I-band slopes for 87 independent Cepheid data sets belonging to 48 external galaxies with nebular oxygen abundance 7.5<=12+log(O/H)<=8.9. We investigated the dependence of the period-Wesenheit (P-W) relations on the metal content and we found that the slopes of optical and NIR P-W relations in external galaxies are similar to the slopes of Large Magellanic Cloud (LMC) Cepheids. They also agree with the theoretical predictions suggesting that the slopes of the P-W relations are independent of the metal content.
- ID:
- ivo://CDS.VizieR/J/A+A/548/A79
- Title:
- INTEGRAL-OMC optically variable sources
- Short Name:
- J/A+A/548/A79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Optical Monitoring Camera (OMC) onboard the High-energy INTEGRAL satellite provides photometry in the V Johnson band. OMC is able to detect optical sources brighter than around V~18, from a previously selected list of potential targets of interest. The first catalogue of variable sources observed by OMC has been developed with observations from October 2002 to February 2010. For each object in the catalogue, the median of the visual magnitude, the magnitude at maximum and minimum brightness in the light curve during the window of observations and the period, when found, are provided.
- ID:
- ivo://CDS.VizieR/J/A+A/495/157
- Title:
- Interstellar extinction in Galactic Center
- Short Name:
- J/A+A/495/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the Spitzer IRAC catalogue of the Galactic Center (GC) point sources (Ramirez et al., 2008ApJS..175..147R) and combine it with new isochrones (Marigo et al., 2008A&A...482..883M) to derive extinctions based on photometry of red giants and asymptotic giant branch (AGB) stars. This new extinction map extends to much higher values of Av than previously available. Our new extinction map of the GC region covers 2.0x1.4deg^2^ (280x200pc at a distance of 8kpc). We apply it to deredden the LPVs found by Glass et al. (2001, Cat. <J/MNRAS/321/77>) near the GC. We make period-magnitude diagrams and compare them to those from other regions of different metallicity. The Glass-LPVs follow well-defined period-luminosity relations (PL) in the IRAC filter bands at 3.6 , 4.5, 5.8, and 8.0um. The period-luminosity relations are similar to those in the Large Magellanic Cloud, suggesting that the PL relation in the IRAC bands is universal. We use ISOGAL data to derive mass-loss rates and find for the Gl ass-LPV sample some correlation between mass-loss and pulsation period, as expected theoretically. The GC has an excess of high luminosity and long period LPVs compared to the Bulge, which supports previous suggestions that it contains a younger stellar population.
