- ID:
- ivo://CDS.VizieR/J/ApJS/219/8
- Title:
- SFR for WISE + SDSS spectroscopic galaxies
- Short Name:
- J/ApJS/219/8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We combine Sloan Digitital Sky Survey (SDSS) and WISE photometry for the full SDSS spectroscopic galaxy sample, creating spectral energy distributions (SEDs) that cover {lambda}=0.4-22{mu}m for an unprecedentedly large and comprehensive sample of 858365 present-epoch galaxies. Using MAGPHYS (da Cunha+ 2008MNRAS.388.1595D), we then simultaneously and consistently model both the attenuated stellar SED and the dust emission at 12 and 22{mu}m, producing robust new calibrations for monochromatic mid-IR star formation rate (SFR) proxies. These modeling results provide the first mid-IR-based view of the bimodality in star formation activity among galaxies, exhibiting the sequence of star-forming galaxies ("main sequence") with a slope of dlogSFR/dlogM_*_=0.80 and a scatter of 0.39dex. We find that these new SFRs along the SF main sequence are systematically lower by a factor of 1.4 than those derived from optical spectroscopy. We show that for most present-day galaxies, the 0.4-22{mu}m SED fits can exquisitely predict the fluxes measured by Herschel at much longer wavelengths. Our analysis also illustrates that the majority of stars in the present-day universe are formed in luminous galaxies (~L*) in and around the "green valley" of the color-luminosity plane. We make publicly available the matched photometry catalog and SED modeling results.
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- ID:
- ivo://CDS.VizieR/J/A+A/619/A45
- Title:
- S5 0716+714 multi-wavelength curves
- Short Name:
- J/A+A/619/A45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The BL Lac object S5 0716+714, a highly variable blazar, underwent an impressive outburst in January 2015 (Phase A), followed by minor activity in February (Phase B). The MAGIC observations were triggered by the optical flux observed in Phase A, corresponding to the brightest ever reported state of the source in the R-band. The comprehensive dataset collected is investigated in order to shed light on the mechanism of the broadband emission. Methods. Multi-wavelength light curves have been studied together with the broadband spectral energy distributions (SEDs). The sample includes data from Effelsberg, OVRO, Metsahovi, VLBI, CARMA, IRAM, SMA, Swift-UVOT, KVA, Tuorla, Steward, RINGO3, KANATA, AZT-8+ST7, Perkins, LX-200, Swift-XRT, NuSTAR, Fermi-LAT and MAGIC. The flaring state of Phase A was detected in all the energy bands, providing for the first time a multi-wavelength sample of simultaneous data from the radio band to the very-high-energy (VHE, E>100GeV). In the constructed SED, the Swift-XRT+NuSTAR data constrain the transition between the synchrotron and inverse Compton components very accurately, while the second peak is constrained from 0.1GeV to 600GeV by Fermi+MAGIC data. The broadband SED cannot be described with a one-zone synchrotron self-Compton model as it severely underestimates the optical flux in order to reproduce the X-ray to {gamma}-ray data. Instead we use a two-zone model. The electric vector position angle (EVPA) shows an unprecedented fast rotation. An estimation of the redshift of the source by combined high-energy (HE, 0.1GeV<E<100GeV) and VHE data provides a value of z=0.31+/-0.02stats+/-0.05sys, confirming the literature value. The data show the VHE emission originating in the entrance and exit of a superluminal knot in and out of a recollimation shock in the inner jet. A shock-shock interaction in the jet seems responsible for the observed flares and EVPA swing. This scenario is also consistent with the SED modeling.
- ID:
- ivo://CDS.VizieR/J/ApJS/224/26
- Title:
- Spectral energy distributions of Roma BZCAT blazars
- Short Name:
- J/ApJS/224/26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We combined multi-wavelength data for blazars from the Roma-BZCAT catalog and analyzed hundreds of X-ray spectra. We present the fluxes and spectral energy distributions (SEDs), in 12 frequency bands from radio to {gamma}-rays, for a final sample of 2214 blazars. Using a model-independent statistical approach, we looked for systematic trends in the SEDs; the most significant trends involved the radio luminosities and X-ray spectral indices of the blazars. We used a principal component analysis (PCA) to determine the basis vectors of the blazar SEDs and, in order to maximize the size of the sample, imputed missing fluxes using the K-nearest neighbors method. Using more than an order of magnitude more data than was available when Fossati et al. first reported trends of SED shape with blazar luminosity, we confirmed the anti-correlation between radio luminosity and synchrotron peak frequency, although with greater scatter than was seen in the smaller sample. The same trend can be seen between bolometric luminosity and synchrotron peak frequency. Finally, we used all of the available blazar data to determine an empirical SED description that depends only on the radio luminosity at 1.4GHz and the redshift. We verified that this statistically significant relation was not a result of the luminosity-luminosity correlations that are natural in flux-limited samples (i.e., where the correlation is actually caused by the redshift rather than the luminosity).
- ID:
- ivo://CDS.VizieR/J/A+A/615/A78
- Title:
- Spectral models for binary products
- Short Name:
- J/A+A/615/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stars stripped of their hydrogen-rich envelope through interaction with a binary companion are generally not considered when accounting for ionizing radiation from stellar populations, despite the expectation that stripped stars emit hard ionizing radiation, form frequently, and live 10-100 times longer than single massive stars. We compute the first grid of evolutionary and spectral models specially made for stars stripped in binaries for a range of progenitor masses (2-20M_{sun}_) and metallicities ranging from solar to values representative for pop II stars. For stripped stars with masses in the range 0.3-7M_{sun}_, we find consistently high effective temperatures (20000-100000K, increasing with mass), small radii (0.2-1R_{sun}_), and high bolometric luminosities, comparable to that of their progenitor before stripping. The spectra show a continuous sequence that naturally bridges subdwarf-type stars at the low-mass end and Wolf-Rayet-like spectra at the high-mass end. For intermediate masses we find hybrid spectral classes showing a mixture of absorption and emission lines. These appear for stars with mass-loss rates of 10^-8^-10^-6^M_{sun}_/yr, which have semi-transparent atmospheres. At low metallicity, substantial hydrogen-rich layers are left at the surface and we predict spectra that resemble O-type stars instead. We obtain spectra undistinguishable from subdwarfs for stripped stars with masses up to 1.7M_{sun}_, which questions whether the widely adopted canonical value of 0.47M_{sun}_ is uniformly valid. Only a handful of stripped stars of intermediate mass have currently been identified observationally. Increasing this sample will provide necessary tests for the physics of interaction, internal mixing, and stellar winds. We use our model spectra to investigate the feasibility to detect stripped stars next to an optically bright companion and recommend systematic searches for their UV excess and possible emission lines, most notably HeII {lambda}4686 in the optical and HeII {lambda}1640 in the UV. Our models are publicly available for further investigations or inclusion in spectral synthesis simulations.
- ID:
- ivo://CDS.VizieR/III/202
- Title:
- Spectrophotometric Catalogue of Stars
- Short Name:
- III/202
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue contains the absolute energy distribution of the 1147 stars of different spectral type and luminosity classes in the range of 3225-7575A with the step 50A. The observations were made in the Fessenkov Astrophysical Institute (AlmaAta,Kazakstan, height 1450m) during 1968-1986 using spectrum scanner with photo-multiplier tube attached to the 50cm Cassegrain telescope. Standards are Beta Ari, Gamma Ori, Beta Tau, Alpha Leo, Eta UMa, Alpha Lyr, Alpha Aql and Alpha Peg, based on the absolute energy distribution of Vega as given Hayes(1985). The average accuracy of the catalogue data is 3.5%.
- ID:
- ivo://CDS.VizieR/III/209
- Title:
- Spectrophotometric Standards
- Short Name:
- III/209
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog contains energy distribution data of 82 stars of 7-8mag belonging to spectral types A0-G2. Spectral energy distribution is presented in the range 3400-7500{AA} with 50{AA} step. The observations were made in the period 1991-1996 by means of the spectrophotometer working at the regime of the photon counting. Scanner was installed at the 60-cm Zeiss reflector of the Sternberg Institute Crimean Station. Eight early type stars were used as spectrophotometic standards: {beta} Ari, {gamma} Ori, {beta} Tau, {alpha} Leo, {eta} UMa, {alpha} Lyr, {alpha} Aql and {alpha} Peg. The accuracy of the monochromatic fluxes is about 2% in the ultraviolet, 1% in the visual range an 1.5-2% for {lambda}>7000{AA}. The energy distribution data are expressed in erg/(cm^2^.s.cm)*10^-6^.
- ID:
- ivo://CDS.VizieR/J/AZh/78/1135
- Title:
- Spectrophotometric standards near DE=+40{deg}
- Short Name:
- J/AZh/78/1135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The second stage to compile a list of regional intermediate-brightness spectrophotometric standards has been completed. It includes the spectral energy distribution for 24 stars with magnitudes 7.0-8.5 near +40{deg} declination. The range 3100-7600{AA} was studied with a spectral resolution of 50{AA}. All the stars are referenced to a single standard the circumpolar star HD 221525. The energy distributions were used to compute color indices in the UBV, WBVR, and UPXYZVS systems,as well as in the system (BT,VT) of the TYCHO catalog.
- ID:
- ivo://CDS.VizieR/J/AZh/71/468
- Title:
- Spectrophotometric Standards near the Pole
- Short Name:
- J/AZh/71/468
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Absolute energy distributions for 13 circumpolar ({delta}>+85deg) stars forming a spectrophotometric version of the North Polar Spectrophotometric Sequence (NPSS) are presented. A-type stars of 5-9mag brightness were studied in the range 3100 to 7750A with resolution of 50A. Observations were made with 0.5-m and 1-m telescopes using Seya-Namioka spectrometers. The relative rms error of results in the region 4000-7000A is 2 to 3%, while at the ends of the studied range it is 3-5%. The primary standard was the circumpolar star HD 221525 (V=5.58, A7IV), and its spectral energy distribution had been determined earlier.
- ID:
- ivo://CDS.VizieR/J/AZh/76/604
- Title:
- Spectrophotometry of S and carbon stars
- Short Name:
- J/AZh/76/604
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The absolute energy distributions in the visual spectra (3200-7600{AA}) of 13 N carbon stars and three S stars have been investigated. The spectral resolution of the data is 50 A and the relative rms error is 2-5%. The data supplement and extend the Almaty and other spectrophotometric catalogs that are lacking in these types of objects.
- ID:
- ivo://CDS.VizieR/J/PAZh/32/672
- Title:
- Spectrophotometry of 77 variable stars
- Short Name:
- J/PAZh/32/672
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of visual and near-infrared spectrophotometric observations for 77 variable stars obtained during 1971-1991 in Chile, Armenia and Bolivia. The quasi-monochromatic extra-atmospheric fluxes from the stars are given in absolute energy units (W/m^2^/m) at all wavelengths of the spectral range at 2.5 nm intervals.
