- ID:
- ivo://CDS.VizieR/J/ApJS/233/6
- Title:
- SNe II light curves & spectra from the CfA
- Short Name:
- J/ApJS/233/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present multiband photometry of 60 spectroscopically confirmed supernovae (SNe): 39 SNe II/IIP, 19 IIn, 1 IIb, and 1 that was originally classified as a IIn but later as a Ibn. Of these, 46 have only optical photometry, 6 have only near-infrared (NIR) photometry, and 8 have both optical and NIR. The median redshift of the sample is 0.016. We also present 195 optical spectra for 48 of the 60 SN. There are 26 optical and 2 NIR light curves of SNe II/IIP with redshifts z>0.01, some of which may give rise to useful distances for cosmological applications. All photometry was obtained between 2000 and 2011 at the Fred Lawrence Whipple Observatory (FLWO), via the 1.2m and 1.3m PAIRITEL telescopes for the optical and NIR, respectively. Each SN was observed in a subset of the u'UBVRIr'i'JHK_s_ bands. There are a total of 2932 optical and 816 NIR light curve points. Optical spectra were obtained using the FLWO 1.5m Tillinghast telescope with the FAST spectrograph and the MMT Telescope with the Blue Channel Spectrograph. Our photometry is in reasonable agreement with select samples from the literature: two-thirds of our star sequences have average V offsets within +/-0.02mag and roughly three-quarters of our light curves have average differences within +/-0.04mag. The data from this work and the literature will provide insight into SN II explosions, help with developing methods for photometric SN classification, and contribute to their use as cosmological distance indicators.
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- ID:
- ivo://CDS.VizieR/J/A+A/646/A22
- Title:
- SN 2020faa multiphotometry and spectra
- Short Name:
- J/A+A/646/A22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present observations of SN 2020faa. This Type II supernova displays a luminous lightcurve that started to rebrighten from an initial decline. We investigate this in relation to the famous supernova iPTF14hls, which received a great deal of attention and multiple interpretations in the literature, but whose nature and source of energy still remain unknown. We demonstrate the great similarity between SN 2020faa and iPTF14hls during the first 6 months, and use this comparison to forecast the evolution of SN 2020faa and to reflect on the less well observed early evolution of iPTF14hls. We present and analyse our observational data, consisting mainly of optical lightcurves from the Zwicky Transient Facility in the gri bands and of a sequence of optical spectra. We construct colour curves and a bolometric lightcurve, and we compare ejecta-velocity and black-body radius evolutions for the two supernovae and for more typical Type II supernovae. The lightcurves show a great similarity with those of iPTF14hls over the first 6 months in luminosity, timescale, and colour. In addition, the spectral evolution of SN 2020faa is that of a Type II supernova, although it probes earlier epochs than those available for iPTF14hls. The similar lightcurve behaviour is suggestive of SN 2020faa being a new iPTF14hls. We present these observations now to advocate follow-up observations, since most of the more striking evolution of supernova iPTF14hls came later, with lightcurve undulations and a spectacular longevity. On the other hand, for SN 2020faa we have better constraints on the explosion epoch than we had for iPTF14hls, and we have been able to spectroscopically monitor it from earlier phases than was done for the more famous sibling.
- ID:
- ivo://CDS.VizieR/J/A+A/630/A76
- Title:
- SN2016hnk photometry and spectroscopy
- Short Name:
- J/A+A/630/A76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive dataset of optical and near-infrared photometry and spectroscopy of type Ia supernova (SN) 2016hnk, combined with integral field spectroscopy (IFS) of its host galaxy, MCG -01-06-070, and nearby environment. Our goal with this complete dataset is to understand the nature of this peculiar object. Methods: Properties of the SN local environment are characterized by means of single stellar population synthesis applied to IFS observations taken two years after the SN exploded. We performed detailed analyses of SN photometric data by studying its peculiar light and color curves. SN 2016hnk spectra were compared to other 1991bg-like SNe Ia, 2002es-like SNe Ia, and Ca-rich transients. In addition, we used abundance stratification modeling to identify the various spectral features in the early phase spectral sequence and also compared the dataset to a modified non-LTE model previously produced for the subluminous SN1999by. Results: SN 2016hnk is consistent with being a subluminous (MB=-16.7mag, sBV=0.43+/-0.03), highly reddened object. The IFS of its host galaxy reveals both a significant amount of dust at the SN location, residual star formation, and a high proportion of old stellar populations in the local environment compared to other locations in the galaxy, which favors an old progenitor for SN 2016hnk. Inspection of a nebular spectrum obtained one year after maximum contains two narrow emission lines attributed to the forbidden [CaII] {lambda}{lambda}7291,7324 doublet with a Doppler shift of 700km/s. Based on various observational diagnostics, we argue that the progenitor of SN 2016hnk was likely a near Chandrasekhar-mass (MCh) carbon-oxygen white dwarf that produced 0.108M_{sun}_ of 56 Ni. Our modeling suggests that the narrow [CaII] features observed in the nebular spectrum are associated with 48 Ca from electron capture during the explosion, which is expected to occur only in white dwarfs that explode near or at the MCh limit.
- ID:
- ivo://CDS.VizieR/J/ApJ/894/19
- Title:
- SOAR spectra of the WD EPIC 228939929
- Short Name:
- J/ApJ/894/19
- Date:
- 03 Dec 2021 00:38:57
- Publisher:
- CDS
- Description:
- We report the discovery of short-period photometric variability and modulated Zeeman-split hydrogen emission in SDSSJ125230.93-023417.72 (EPIC 228939929), a variable white dwarf star observed at long cadence in K2 Campaign 10. The behavior is associated with a magnetic (B=5.0MG) spot on the stellar surface, making the 317.278s period a direct measurement of the stellar rotation rate. This object is therefore the fastest-rotating, apparently isolated (without a stellar companion) white dwarf yet discovered and the second found to exhibit chromospheric Balmer emission after GD 356, in which the emission has been attributed to a unipolar inductor mechanism driven by a possible rocky planet. We explore the properties and behavior of this object, and consider whether its evolution may hold implications for white dwarf mergers and their remnants.
- ID:
- ivo://CDS.VizieR/J/ApJS/208/7
- Title:
- Sodium excess objects. I. SDSS-DR7
- Short Name:
- J/ApJS/208/7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Several studies have reported the presence of sodium excess objects having neutral atomic absorption lines at 5895{AA} (Na.D) and 8190{AA} that are deeper than expected based on stellar population models that match the stellar continuum. The origin of these lines is therefore hotly debated. van Dokkum & Conroy (2010Natur.468..940V) proposed that low-mass stars (<~0.3M_{sun}_) are more prevalent in massive early-type galaxies, which may lead to a strong Na I 8190 line strength. It is necessary to test this prediction, however, against other prominent optical line indices such as Na.D, Mg b, and Fe 5270, which can be measured with a significantly higher signal-to-noise ratio than Na I 8190. We identified a new sample of roughly 1000 Na.D excess objects (NEOs; ~8% of galaxies in the sample) based on Na.D line strength in the redshift range 0.00<=z<=0.08 from the Sloan Digital Sky Survey (SDSS) DR7 through detailed analysis of galaxy spectra. We explore the properties of these new objects here. The novelty of this work is that the galaxies were carefully identified through direct visual inspection of SDSS images, and we systematically compared the properties of NEOs and those of a control sample of galaxies with normal Na.D line strengths. We note that the majority of galaxies with high velocity dispersions ({sigma}_e_>250km/s) show Na.D excesses.
- ID:
- ivo://CDS.VizieR/III/179
- Title:
- Southern MK Standards 5800-10200A
- Short Name:
- III/179
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectra are presented for MK standards in the wavelength range 580-1020nm. The stars cover the normal spectral types O to M and luminosity types I, III, and V. In addition, a small number of peculiar stars are included. The data are in 137 FITS files, in the "fits" subdirectory. The list of the 137 stars is included in the "stars.dat" file; note that the list is not identical to the stars listed in Table1 of the paper.
- ID:
- ivo://CDS.VizieR/J/ApJ/884/L31
- Title:
- Spectra & HST obs. of gal. in 1ES1553+113 field
- Short Name:
- J/ApJ/884/L31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The relationship between galaxies and the state/chemical enrichment of the warm-hot intergalactic medium (WHIM) expected to dominate the baryon budget at low-z provides sensitive constraints on structure formation and galaxy evolution models. We present a deep redshift survey in the field of 1ES1553+113, a blazar with a unique combination of ultraviolet (UV)+X-ray spectra for surveys of the circumgalactic/intergalactic medium (CGM/IGM). Nicastro+ (2018Natur.558..406N) reported the detection of two OVII WHIM absorbers at z=0.4339 and 0.3551 in its spectrum, suggesting that the WHIM is metal rich and sufficient to close the missing baryons problem. Our survey indicates that the blazar is a member of a z=0.433 group and that the higher-z OVII candidate arises from its intragroup medium. The resulting bias precludes its use in baryon censuses. The z=0.3551 candidate occurs in an isolated environment 630kpc from the nearest galaxy (with stellar mass logM_*_/M_{sun}_~9.7), which we show is unexpected for the WHIM. Finally, we characterize the galactic environments of broad HI Ly{alpha} absorbers (Doppler widths of b=40-80km/s; T<~4x10^5^K) that provide metallicity-independent WHIM probes. On average, broad Ly{alpha} absorbers are ~2x closer to the nearest luminous (L>0.25L*) galaxy (700kpc) than narrow (b<30km/s; T<~4x10^5^K) ones (1300kpc) but ~2x further than OVI absorbers (350kpc). These observations suggest that gravitational collapse heats portions of the IGM to form the WHIM, but with feedback that does not enrich the IGM far beyond galaxy/group halos to levels currently observable in UV/X-ray metal lines.
- ID:
- ivo://CDS.VizieR/J/ApJ/771/114
- Title:
- Spectral analysis of 100 evolved PNe from SPM
- Short Name:
- J/ApJ/771/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have selected a group of 100 evolved planetary nebulae (PNe) and study their kinematics based upon spatially-resolved, long-slit, echelle spectroscopy. The data have been drawn from the San Pedro Martir Kinematic Catalogue of PNe (SPM Catalogue). The aim is to characterize in detail the global kinematics of PNe at advanced stages of evolution with the largest sample of homogenous data used to date for this purpose. The results reveal two groups that share kinematics, morphology, and photo-ionization characteristics of the nebular shell and central star luminosities at the different late stages under study. The typical flow velocities we measure are usually larger than seen in earlier evolutionary stages, with the largest velocities occurring in objects with very weak or absent [NII]{lambda}6584 line emission, by all indications the least evolved objects in our sample. The most evolved objects expand more slowly. This apparent deceleration during the final stage of PNe evolution is predicted by hydrodynamical models, but other explanations are also possible. These results provide a template for comparison with the predictions of theoretical models.
- ID:
- ivo://CDS.VizieR/J/A+A/530/A146
- Title:
- Spectral and UBV analysis of {epsilon} Aur
- Short Name:
- J/A+A/530/A146
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A series of 353 red electronic spectra (from three observatories, mostly from 6300 to 6700{AA}) obtained between 1994 and 2010, and of 171 UBV photometric observations (from two observatories) of the 2010 eclipse, were analyzed in an effort to better understand epsilon Aur, the well-known, but still enigmatic eclipsing binary with the longest known orbital period (~27yrs).
- ID:
- ivo://CDS.VizieR/J/AJ/160/52
- Title:
- Spectral classification for 631 {rho}Puppis stars
- Short Name:
- J/AJ/160/52
- Date:
- 09 Mar 2022
- Publisher:
- CDS
- Description:
- The {rho}Puppis stars are mid-F-type stars that show peculiar chemical-abundance patterns similar to those of the Am stars. Typically they exhibit overabundances of iron-peak elements such as Fe and Ni and s- and r-process elements such as Sr and Eu, and underabundances of certain other elements including He, Ca, and Sc. It has been proposed that these stars are evolving Am stars passing through the short-lived phase that occurs between the re-establishment of convection and the consequent erasure of their chemical peculiarities. In this paper we suggest a second hypothesis: these stars may have acquired their peculiar abundance patterns in a fashion similar to the Barium stars, i.e., they may have gained the s-process element enhancements via mass transfer from a once asymptotic giant-branch companion star, now turned white dwarf. This study will detail our efforts to investigate the {rho}Puppis stars with regard to these two hypotheses, with a view to understanding these stars and their significance in terms of stellar evolution. We have performed a spectral classification survey, and a detailed chemical-abundance analysis of selected {rho}Puppis stars. This paper gives an overview of the {rho}Puppis stars and describes the spectral classification survey which has increased the number of {rho}Puppis stars currently known from 6 to 49. A future paper will describe the chemical-abundance analysis which should provide insight into the nature of these stars.