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- ID:
- ivo://CDS.VizieR/J/PAZh/30/297
- Title:
- BVRI and fluxes of HM Sge in 1986-2000
- Short Name:
- J/PAZh/30/297
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of BVRI photometric and spectroscopic observations of symbiotic Nova HM Sagittae were made in 1986-2002.
- ID:
- ivo://CDS.VizieR/J/ApJ/888/30
- Title:
- BVRI and spectroscopic light curves of S5 0716+714
- Short Name:
- J/ApJ/888/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to study short timescale optical variability of {gamma}-ray blazar S5 0716+714, quasi-simultaneous spectroscopic and multiband photometric observations were performed from 2018 November to 2019 March with the 2.4m optical telescope located at Lijiang Observatory of Yunnan Observatories. The observed spectra are well fitted with a power law F_{lambda}_=A{lambda}^-{alpha}^ (spectral index {alpha}>0). Correlations found between {dot}{alpha}, {dot}A, {dot}A/A, {dot}F_{lambda}_, and {dot}F_{lambda}_/F_{lambda}_ are consistent with the trend of bluer-when-brighter (BWB). It is the same case for colors, magnitudes, color variation rates, and magnitude variation rates of photometric observations. The variations of {alpha} lead those of F_{lambda}_. Also, the color variations lead magnitude variations. The observational data are mostly distributed in the I(+,+) and III(-,-) quadrants of the coordinate system. Both spectroscopic and photometric observations show BWB behaviors in S5 0716+714. The observed BWB may be explained by the shock-jet model, and its appearance may depend on the relative position of the observational frequency ranges with respect to the synchrotron peak frequencies, e.g., at the left of the peak frequencies. Fractional variability amplitudes are F_var_~40% for both spectroscopic and photometric observations. Variations of {alpha} indicate variations of relativistic electron distribution producing the optical spectra.
- ID:
- ivo://CDS.VizieR/J/ApJ/875/136
- Title:
- BVRI, spectra & IR obs. of type II-P SN2017eaw
- Short Name:
- J/ApJ/875/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present extensive optical photometric and spectroscopic observations, from 4 to 482 days after explosion, of the Type II-plateau (II-P) supernova (SN) 2017eaw in NGC 6946. SN 2017eaw is a normal SN II-P intermediate in properties between, for example, SN 1999em and SN 2012aw and the more luminous SN 2004et, also in NGC6946. We have determined that the extinction to SN 2017eaw is primarily due to the Galactic foreground and that the SN site metallicity is likely subsolar. We have also independently confirmed a tip-of-the-red-giant-branch (TRGB) distance to NGC 6946 of 7.73+/-0.78Mpc. The distances to the SN that we have also estimated via both the standardized candle method and expanding photosphere method corroborate the TRGB distance. We confirm the SN progenitor identity in pre-explosion archival Hubble Space Telescope (HST) and Spitzer Space Telescope images, via imaging of the SN through our HST Target of Opportunity program. Detailed modeling of the progenitor's spectral energy distribution indicates that the star was a dusty, luminous red supergiant consistent with an initial mass of ~15M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/PAZh/44/383
- Title:
- Byurakan-IRAS galaxies (BIG) with SDSS spectra
- Short Name:
- J/PAZh/44/383
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The sample of Byurakan-IRAS galaxies (BIG) has been created based on optical identifications of IRAS Point Source Catalog (PSC) at high galactic latitudes. As a result, 1178 galaxies have been identified. 172 of them have been observed spectroscopically with Byurakan Astrophysical Observatory (BAO, Armenia) 2.6m, Special Astrophysical Observatory (SAO, Russia) 6m and Observatoire de Haute Provence (OHP, France) 1.93m telescopes. Later on, spectra were obtained for more 83 BIG objects in Sloan Digital Sky Survey (SDSS). We have extracted and studied these spectra, classified them and measured spectral features. Diagnostic diagrams have been built to distinguish starbursts (SB), LINERs and Seyfert galaxies. Cross-correlations were made for these objects with multiwavelength (MW) catalogues and their physical properties were studied. Among these 83 objects, 55 HII, 8 Seyfert galaxies, 2 LINERs, 4 other AGN, 6 composite spectrum objects, and 8 other emission-line galaxies have been revealed. Three of these objects are Ultra-Luminous InfraRed Galaxies (ULIRG).
- ID:
- ivo://CDS.VizieR/J/A+AS/146/103
- Title:
- CaII H&K to CaII IRT echelle spectra
- Short Name:
- J/A+AS/146/103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the third paper of a series aimed at studying the chromosphere of active binary systems using the information provided for several optical spectroscopic features. High resolution echelle spectra including all the optical chromospheric activity indicators from the CaII H&K to CaII IRT lines are analysed here for 16 systems. The chromospheric contribution in these lines has been determined using the spectral subtraction technique. Very broad wings have been found in the subtracted H{alpha} profile of the very active star HU Vir. These profiles are well matched using a two-component Gaussian fit (narrow and broad) and the broad component can be interpreted as arising from microflaring. Red-shifted absorption features in the H{alpha} line have been detected in several systems and excess emission in the blue wing of FG UMa was also detected. These features indicate that several dynamical processes, or a combination of them, may be involved. Using the E_H{alpha}_/E_H{beta}_ ratio as a diagnostic we have detected prominence-like extended material viewed off the limb in many stars of the sample, and prominences viewed against the disk at some orbital phases in the dwarfs OU Gem and BF Lyn. The He I D_3_ line has been detected as an absorption feature in mainly all the giants of the sample. Total filling-in of the He I D_3_, probably due to microflaring activity, is observed in HU Vir. Self-absorption with red asymmetry is detected in the CaII H&K lines of the giants 12 Cam, FG UMa and BM CVn. All the stars analysed show clear filled-in CaII IRT lines or even notable emission reversal. The small values of the E_8542_/E_8498_ ratio we have found indicate CaII IRT emission arises from plage-like regions. Orbital phase modulation of the chromospheric emission has been detected in some systems, in the case of HU Vir evidence of an active longitude area has been found.
- ID:
- ivo://CDS.VizieR/J/AJ/136/1039
- Title:
- CaII index of SMC red giant branch stars
- Short Name:
- J/AJ/136/1039
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present stellar metallicities derived from Ca II triplet spectroscopy in over 350 red giant branch stars in 13 fields distributed in different positions in the Small Magellanic Cloud, ranging from ~1{deg} to ~4{deg} from its center. In the innermost fields, the average metallicity is [Fe/H]~-1. This value decreases when we move away toward outermost regions. This is the first detection of a spectroscopic metallicity gradient in this galaxy. We show that the metallicity gradient is related to an age gradient, in the sense that more metal-rich stars, which are also younger, are concentrated in the central regions of the galaxy.
- ID:
- ivo://CDS.VizieR/J/A+A/582/A59
- Title:
- CaIIK spectra of 7 Galactic and MC open clusters
- Short Name:
- J/A+A/582/A59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The large and small-scale (pc) structure of the Galactic interstellar medium can be investigated by utilising spectra of early- type stellar probes of known distances in the same region of the sky. This paper determines the variation in line strength of CaII at 3933.661{AA} as a function of probe separation for a large sample of stars, including a number of sightlines in the Magellanic Clouds. FLAMES-GIRAFFE data taken with the Very Large Telescope towards early-type stars in 3 Galactic and 4 Magellanic open clusters in CaII are used to obtain the velocity, equivalent width, column density, and line width of interstellar Galactic calcium for a total of 657 stars, of which 443 are Magellanic Cloud sightlines. In each cluster there are between 43 and 111 stars observed. Additionally, FEROS and UVES CaII K and NaI D spectra of 21 Galactic and 154 Magellanic early-type stars are presented and combined with data from the literature to study the calcium column density - parallax relationship.
- ID:
- ivo://CDS.VizieR/J/AJ/138/517
- Title:
- CaII spectroscopy of SMC red giants
- Short Name:
- J/AJ/138/517
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained near-infrared spectra covering the CaII triplet lines for a large number of stars associated with 16 Small Magellanic Cloud (SMC) clusters using the VLT + FORS2. These data compose the largest available sample of SMC clusters with spectroscopically derived abundances and velocities. Our clusters span a wide range of ages and provide good areal coverage of the galaxy.
- ID:
- ivo://CDS.VizieR/J/A+A/632/A69
- Title:
- CaII transmission spectrum of WASP-33b and KELT-9b
- Short Name:
- J/A+A/632/A69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ultra-hot Jupiters are emerging as a new class of exoplanets. Studying their chemical compositions and temperature structures will improve the understanding of their mass loss rate as well as their formation and evolution. We present the detection of ionized calcium in the two hottest giant exoplanets - KELT-9b and WASP-33b. By utilizing transit datasets from CARMENES and HARPS-N observations, we achieved high confidence level detections of CaII using the cross-correlation method. We further obtain the transmission spectra around the individual lines of the CaII H&K doublet and the near-infrared triplet, and measure their line profiles. The CaII H&K lines have an average line depth of 2.02+/-0.17% (effective radius of 1.56Rp) for WASP-33b and an average line depth of 0.78+/-0.04% (effective radius of 1.47Rp) for KELT-9b, which indicates that the absorptions are from very high upper atmosphere layers close to the planetary Roche lobes. The observed CaII lines are significantly deeper than the predicted values from the hydrostatic models. Such a discrepancy is probably a result of hydrodynamic outflow that transports a significant amount of CaII into the upper atmosphere. The prominent CaII detection with the lack of significant CaI detection implies that calcium is mostly ionized in the upper atmospheres of the two planets.
