- ID:
- ivo://CDS.VizieR/J/ApJ/805/74
- Title:
- SN2014J Swift/UVOT light curves
- Short Name:
- J/ApJ/805/74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical and ultraviolet (UV) photometry and spectra of the very nearby and highly reddened supernova (SN) 2014J in M82 obtained with the Swift Ultra-Violet/Optical Telescope (UVOT). Comparison of the UVOT grism spectra of SN 2014J with Hubble Space Telescope observations of SN2011fe or UVOT grism spectra of SN 2012fr are consistent with an extinction law with a low value of R_V_~1.4. The high reddening causes the detected photon distribution in the broadband UV filters to have a much longer effective wavelength than for an unreddened SN. The light curve evolution is consistent with this shift and does not show a flattening due to photons being scattered back into the line of sight (LOS). The light curve shapes and color evolution are inconsistent with a contribution scattered into the LOS by circumstellar dust. We conclude that most or all of the high reddening must come from interstellar dust. We show that even for a single dust composition, there is not a unique reddening law caused by circumstellar scattering. Rather, when considering scattering from a time-variable source, we confirm earlier studies that the reddening law is a function of the dust geometry, column density, and epoch. We also show how an assumed geometry of dust as a foreground sheet in mixed stellar/dust systems will lead to a higher inferred R_V_. Rather than assuming the dust around SNe is peculiar, SNe may be useful probes of the interstellar reddening laws in other galaxies.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/611/A58
- Title:
- SN 2007on and SN 2011iv light curves
- Short Name:
- J/A+A/611/A58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of ultraviolet (UV) to near-infrared observations of the fast-declining Type Ia supernovae (SNe Ia) 2007on and 2011iv, hosted by the Fornax cluster member NGC 1404. The B-band light curves of SN 2007on and SN 2011iv are characterised by {Delta}m15(B) decline-rate values of 1.96mag and 1.77mag, respectively. Although they have similar decline rates, their peak B- and H-band magnitudes differ by ~0.60mag and ~0.35mag, respectively. After correcting for the luminosity vs. decline rate and the luminosity vs. colour relations, the peak B-band and H-band light curves provide distances that differ by ~14% and ~9%, respectively. These findings serve as a cautionary tale for the use of transitional SNe Ia located in early-type hosts in the quest to measure cosmological parameters. Interestingly, even though SN 2011iv is brighter and bluer at early times, by three weeks past maximum and extending over several months, its B-V colour is 0.12mag redder than that of SN 2007on. To reconcile this unusual behaviour, we turn to guidance from a suite of spherical one-dimensional Chandrasekhar-mass delayed-detonation explosion models. In this context, ^56^Ni production depends on both the so-called transition density and the central density of the progenitor white dwarf. To first order, the transition density drives the luminosity-width relation, while the central density is an important second-order parameter. Within this context, the differences in the B-V colour evolution along the Lira regime suggest that the progenitor of SN 2011iv had a higher central density than SN 2007on.
- ID:
- ivo://CDS.VizieR/J/A+A/422/337
- Title:
- Solar EUV Post-Eruptive Arcades
- Short Name:
- J/A+A/422/337
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Extreme ultraviolet Imaging Telescope (EIT) on board the Solar and Heliospheric Observatory (SOHO) spacecraft provides unique observations of dynamic processes in the low corona. The EIT 195{AA} data taken from 1997 to the end of 2002 were investigated to study the basic physical properties of post-eruptive arcades (PEAs) and their relationship with coronal mass ejections (CMEs) as detected by SOHO/LASCO (Large Angle Spectrometric Coronagraph). Over the investigated time period, 236 PEA events have been identified in total. For each PEA, its EUV lifetime as derived from the emission time at 195{AA}, its heliographic position and length, and its corresponding photospheric source region inferred from SOHO/MDI (Michelson Doppler Imager) data has been studied, as well as the variation of these parameters over the investigated phase of solar cycle 23.
- ID:
- ivo://CDS.VizieR/J/ApJ/821/56
- Title:
- Space telescope RM project. III. NGC 5548 LCs
- Short Name:
- J/ApJ/821/56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present ground-based optical photometric monitoring data for NGC5548, part of an extended multiwavelength reverberation mapping campaign. The light curves have nearly daily cadence from 2014 January to July in nine filters (BVRI and ugriz). Combined with ultraviolet data from the Hubble Space Telescope and Swift, we confirm significant time delays between the continuum bands as a function of wavelength, extending the wavelength coverage from 1158{AA} to the z band (~9160{AA}). We find that the lags at wavelengths longer than the V band are equal to or greater than the lags of high-ionization-state emission lines (such as HeII{lambda}1640 and {lambda}4686), suggesting that the continuum-emitting source is of a physical size comparable to the inner broad-line region (BLR). The trend of lag with wavelength is broadly consistent with the prediction for continuum reprocessing by an accretion disk with {tau}{propto}{lambda}^4/3^. However, the lags also imply a disk radius that is 3 times larger than the prediction from standard thin-disk theory, assuming that the bolometric luminosity is 10% of the Eddington luminosity (L=0.1L_Edd_). Using optical spectra from the Large Binocular Telescope, we estimate the bias of the interband continuum lags due to BLR emission observed in the filters. We find that the bias for filters with high levels of BLR contamination (~20%) can be important for the shortest continuum lags and likely has a significant impact on the u and U bands owing to Balmer continuum emission.
- ID:
- ivo://CDS.VizieR/J/ApJS/193/13
- Title:
- Spitzer/IRAC sources in the EGS I. SEDs
- Short Name:
- J/ApJS/193/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an IRAC 3.6+4.5um selected catalog in the Extended Groth Strip (EGS) containing photometry from the ultraviolet to the far-infrared and stellar parameters derived from the analysis of the multi-wavelength data. In this paper, we describe the method used to build coherent spectral energy distributions (SEDs) for all the sources. In a forthcoming companion paper, we analyze those SEDs to obtain robust estimations of stellar parameters such as photometric redshifts, stellar masses, and star formation rates. The catalog comprises 76936 sources with [3.6]<=23.75mag (85% completeness level of the IRAC survey in the EGS) over 0.48deg^2^. For approximately 16% of this sample, we are able to deconvolve the IRAC data to obtain robust fluxes for the multiple counterparts found in ground-based optical images. Typically, the SEDs of the IRAC sources in our catalog count with more than 15 photometric data points, spanning from the ultraviolet wavelengths probed by GALEX to the far-infrared observed by Spitzer, and going through ground- and space-based optical and near-infrared data taken with 2-8m class telescopes. Approximately 95% and 90% of all IRAC sources are detected in the deepest optical and near-infrared bands. These fractions are reduced to 85% and 70% for S/N>5 detections in each band. Only 10% of the sources in the catalog have optical spectroscopy and redshift estimations. Almost 20% and 2% of the sources are detected by MIPS at 24 and 70um, respectively. We also cross-correlate our catalog with public X-ray and radio catalogs.
196. Star Clusters in M33
- ID:
- ivo://CDS.VizieR/J/ApJS/122/431
- Title:
- Star Clusters in M33
- Short Name:
- J/ApJS/122/431
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present the discovery of 60 star clusters in 20 multiband Hubble Space Telescope (HST) WFPC2 fields in M33. The fields sample a variety of environments, from outer regions to spiral arms and central regions, as well as a range of galactocentric distances. The HST spatial resolution allowed us to penetrate the crowded, spiral arm regions of M33 yielding the first unbiased, representative sample of star clusters for this galaxy. We discuss the separation of clusters from stellar sources, and from other extended sources such as star-forming regions, H II regions, and supernova remnants. For the clusters we present multiband images and discuss morphology, location, and integrated photometry. Measured cluster colors and magnitudes are presented. The cluster density in our sample as a function of galactocentric distance yields an estimate of 690 total clusters in M33.
- ID:
- ivo://CDS.VizieR/J/MNRAS/482/560
- Title:
- Star formation in nearby galaxies
- Short Name:
- J/MNRAS/482/560
- Date:
- 18 Jan 2022 13:35:08
- Publisher:
- CDS
- Description:
- We present multiwavelength global star formation rate (SFR) estimates for 326 galaxies from the Star Formation Reference Survey in order to determine the mutual scatter and range of validity of different indicators. The widely used empirical SFR recipes based on 1.4GHz continuum, 8.0um polycyclic aromatic hydrocarbons (PAHs), and a combination of far-infrared (FIR) plus ultraviolet (UV) emission are mutually consistent with scatter of <~0.3dex. The scatter is even smaller, <~0.24dex, in the intermediate luminosity range 9.3<log(L_60um_/L_{sun}_)<10.7. The data prefer a non-linear relation between 1.4GHz luminosity and other SFR measures. PAH luminosity underestimates SFR for galaxies with strong UV emission. A bolometric extinction correction to far-UV luminosity yields SFR within 0.2dex of the total SFR estimate, but extinction corrections based on UV spectral slope or nuclear Balmer decrement give SFRs that may differ from the total SFR by up to 2dex. However, for the minority of galaxies with UV luminosity >5x10^9^L_{sun}_ or with implied far-UV extinction <1mag, the UV spectral slope gives extinction corrections with 0.22dex uncertainty.
- ID:
- ivo://CDS.VizieR/J/ApJ/761/97
- Title:
- Star Formation in Radio Survey (SFRS): 33GHz obs.
- Short Name:
- J/ApJ/761/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 33GHz photometry of 103 galaxy nuclei and extranuclear star-forming complexes taken with the Green Bank Telescope (GBT) as part of the Star Formation in Radio Survey (SFRS). Among the sources without evidence for an active galactic nucleus, and also having lower frequency radio data, we find a median thermal fraction at 33GHz of {approx}76% with a dispersion of {approx}24%. For all sources resolved on scales <~0.5kpc, the thermal fraction is even larger, being >~90%. This suggests that the rest-frame 33GHz emission provides a sensitive measure of the ionizing photon rate from young star-forming regions, thus making it a robust star formation rate (SFR) indicator. Taking the 33 GHz SFRs as a reference, we investigate other empirical calibrations relying on different combinations of warm 24{mu}m dust, total infrared (IR; 8-1000{mu}m), H{alpha} line, and far-UV continuum emission. The recipes derived here generally agree with others found in the literature, albeit with a large dispersion that most likely stems from a combination of effects. Comparing the 33GHz to total IR flux ratios as a function of the radio spectral index, measured between 1.7 and 33GHz, we find that the ratio increases as the radio spectral index flattens which does not appear to be a distance effect. Consequently, the ratio of non-thermal to total IR emission appears relatively constant, suggesting only moderate variations in the cosmic-ray electron injection spectrum and ratio of synchrotron to total cooling processes among star-forming complexes. Assuming that this trend solely arises from an increase in the thermal fraction sets a maximum on the scatter of the non-thermal spectral indices among the star-forming regions of {sigma}_{alpha}_NT<~0.13.
- ID:
- ivo://CDS.VizieR/J/MNRAS/453/1965
- Title:
- Star-forming compact groups
- Short Name:
- J/MNRAS/453/1965
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a local sample (z<0.15) of 280 star-forming compact groups (SFCGs) of galaxies identified in the ultraviolet Galaxy Evolution EXplorer (GALEX) All-sky Imaging Survey (AIS). So far, just one prototypical example of SFCG, the Blue Infalling Group, has been studied in detail in the Local Universe. The sample of SFCGs is mainly the result of applying a Friends-of-Friends group finder in the space of celestial coordinates with a maximum linking-length of 1.5 arcmin and choosing groups with a minimum number of four members of bright UV-emitting 17<FUV<20.5 sources (mostly galaxies) from the GALEX/AIS catalogue. The result from the search are 280 galaxy groups composed by 226, 39, 11 and 4 groups of four, five, six and seven bright ultraviolet (UV) members, respectively. Only 59 of these 280 newly identified SFCGs have a previous catalogued group counterpart. Group redshifts are available for at least one member in 75 per cent of the SFCGs, and over 40 per cent of the SFCGs have redshifts measured for two or more galaxies. 26 of the SFCGs appear to be located in the infalling regions of clusters with known redshift. The SFCG sample presents a combination of properties different from the group samples studied up to now, such as low-velocity dispersions (sigma_l-o-s_~120km/s), small crossing-times (H_0_t_c_~0.05) and high star formation content (95 per cent of star-forming galaxies). This points to the SFCGs being in an evolutionary stage distinct from those groups selected in the optical and near-infrared ranges. Once redshifts are obtained to discard interlopers, SFCGs will constitute a unique sample of SFCGs.
- ID:
- ivo://CDS.VizieR/J/A+A/303/661
- Title:
- Star-forming galaxies in the Coma Cluster
- Short Name:
- J/A+A/303/661
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a field of 1deg radius centered in the Coma cluster of galaxies, UV ({lambda}=2000 A) observations with a 40-cm balloon-borne imaging telescope (FOCA) have provided a list of 442 UV sources brighter than m_UV_=18, which are identified in the Godwin (1983) catalogue. 254 are identified as galaxies, 178 as star-like objects and 10 as galaxy-star pairs, unresolved in the UV image.