- ID:
- ivo://CDS.VizieR/J/ApJS/254/26
- Title:
- Identifying 3FHL. V. CTIO-COSMOS spectra
- Short Name:
- J/ApJS/254/26
- Date:
- 19 Jan 2022 00:35:09
- Publisher:
- CDS
- Description:
- As a follow-up to the optical spectroscopic campaign aimed at achieving completeness in the Third Catalog of Hard Fermi-LAT Sources (3FHL), we present here the results of a sample of 28 blazars of an uncertain type observed using the 4m telescope at Cerro Tololo Inter-American Observatory in Chile. Out of these 28 sources, we find that 25 are BL Lacertae objects (BL Lacs) and 3 are flat-spectrum radio quasars (FSRQs). We measure redshifts or lower limits for 16 of these blazars, and it is observed that the 12 remaining blazars have featureless optical spectra. These results are part of a more extended optical spectroscopy follow-up campaign for 3FHL blazars, where, until now, 51 blazars of an uncertain type have been classified into BL Lac and FSRQ categories. Furthermore, this campaign has resulted in redshift measurements and lower limits for 15 of these sources. Our results contribute toward attaining a complete sample of blazars above 10 GeV, which then will be crucial in extending our knowledge on blazar emission mechanisms and the extragalactic background light.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/581/A65
- Title:
- IFU observations of NGC 4191
- Short Name:
- J/A+A/581/A65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We here distinguish two counter-rotating stellar components in NGC 4191 and characterize their physical properties such as kinematics, size, morphology, age, metallicity. We obtained integral field spectroscopic observations with VIRUS-W and used a spectroscopic decomposition technique to separate the contribution of two stellar components to the observed galaxy spectrum. We also performed a photometric decomposition, modeling the galaxy with a Sersic bulge and two exponential disks of different scale length, with the aim of associating these structural components with the kinematic components. We then measured the equivalent width of the absorption line indices on the best-fit models that represent the kinematic components and compared our measurements to the predictions of stellar population models that also account for the variable abundance ratio of {alpha} elements.
- ID:
- ivo://CDS.VizieR/J/ApJS/164/1
- Title:
- IGM absorbers toward HE 0226-4110
- Short Name:
- J/ApJS/164/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the FUSE (Far Ultraviolet Spectroscopic Explorer) and HST (Hubble Space Telescope) STIS E140M spectra of HE 0226-4110 (z=0.495). We detect 56 Lyman absorbers and five OVI absorbers.
1154. IGRINS spectral library
- ID:
- ivo://CDS.VizieR/J/ApJS/238/29
- Title:
- IGRINS spectral library
- Short Name:
- J/ApJS/238/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a library of high-resolution (R~45000) and high signal-to-noise ratio (S/N>=200) near-infrared spectra for stars of a wide range of spectral types and luminosity classes. The spectra were obtained with the Immersion GRating INfrared Spectrograph covering the full range of the H (1.496-1.780{mu}m) and K (2.080-2.460{mu}m) atmospheric windows. The targets were primarily selected for being MK standard stars covering a wide range of effective temperatures and surface gravities, with metallicities close to the solar value. Currently, the library includes flux-calibrated and telluric-absorption-corrected spectra of 84 stars, with prospects for expansion to provide denser coverage of the parametric space. Throughout the H and K atmospheric windows, we identified spectral lines that are sensitive to Teff or logg and defined corresponding spectral indices. We also provide their equivalent widths (EWs). For those indices, we derive empirical relations between the measured EWs and the stellar atmospheric parameters. Therefore, the derived empirical equations can be used to calculate the Teff and logg of a star without requiring stellar atmospheric models.
- ID:
- ivo://CDS.VizieR/J/A+A/608/A36
- Title:
- IGR J19552+0044 BV light curves and spectra
- Short Name:
- J/A+A/608/A36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on XMM-Newton X-ray observations IGR J19552+0044 appears to be either a pre-polar or an asynchronous polar. Aims. We conducted follow-up optical observations to identify the sources and periods of variability precisely and to classify this X-ray source correctly. Extensive multicolor photometric and medium- to high-resolution spectroscopy observations were performed and period search codes were applied to sort out the complex variability of the object. We found firm evidence of discording spectroscopic (81.29+/-0.01m) and photometric (83.599+/-0.002m) periods that we ascribe to the white dwarf (WD) spin period and binary orbital period, respectively. This confirms that IGR J19552+0044 is an asynchronous polar. Wavelength dependent variability and its continuously changing shape point at a cyclotron emission from a magnetic WD with a relatively low magnetic field below 20MG. The difference between the WD spin period and the binary orbital period proves that IGR J19552+0044 is a polar with the largest known degree of asynchronism (0.97 or 3%).
- ID:
- ivo://CDS.VizieR/J/A+A/625/A27
- Title:
- II Pegasi spectra with PEPSI
- Short Name:
- J/A+A/625/A27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a temperature and a magnetic-field surface map of the K2 subgiant of the active binary II Peg. Employed are high resolution Stokes IV spectra obtained with the new Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT). Fourteen average line profiles are inverted using our iMap code. We have employed an iterative regularization scheme without the need of a penalty function and incorporate a physical 3D description of the surface field vector. The spectral resolution of our data is 130000 which converts to 20 resolution elements across the disk of II Peg. Our main result is that the temperature features on II Peg closely correlate with its magnetic field topology. We find a warm spot (350K warmer with respect to the effective temperature) of positive polarity and radial field density of 1.1kG coexisting with a cool spot (780K cooler) of negative polarity of 2kG. Several other cool features are reconstructed containing both polarities and with (radial) field densities of up to 2kG. The largest cool spot is reconstructed with a temperature contrast of 550K, an area of almost 10% of the visible hemisphere, and with a multipolar magnetic morphology. A meridional and an azimuthal component of the field of up to +/-500G is detected in two surface regions between spots with strong radial fields but different polarities. A force-free magnetic-field extrapolation suggests that the different polarities of cool spots and the positive polarity of warm spots are physically related through a system of coronal loops of typical height of ~=2R*. While the H{alpha} line core and its red-side wing exhibit variations throughout all rotational phases, a major increase of blue-shifted H{alpha} emission was seen for the phases when the warm spot is approaching the stellar central meridian indicating high-velocity mass motion within its loop. Active stars such as II Peg can show coexisting cool and warm spots on the surface that we interpret resulting from two different formation mechanisms. We explain the warm spots due to photospheric heating by a shock front from a siphon-type flow between regions of different polarities while the majority of the cool spots is likely formed due to the expected convective suppression like on the Sun.
1157. IKS
- ID:
- ivo://padc.obspm.planeto/iks/q/epn_core
- Title:
- IKS
- Short Name:
- IKS
- Date:
- 26 Feb 2025 08:37:14
- Publisher:
- Paris Astronomical Data Centre - LESIA
- Description:
- Measurements of comet Halley in the spectral channel of IKS on board the Vega-1 spacecraft. Data are retrieved from the PDS Small Bodies Node data set (2011 reformatted version) and updated. The data set consists in 101 tables providing the radiance spectrum of comet Halley from various distances, plus two composite spectra. For details and further references, see: Combes M. et al., 1988, The 2.5-12 micron Spectrum of Comet Halley from the IKS-VEGA Experiment, Icarus, 76, 404-436 [1988Icar...76..404C]
- ID:
- ivo://CDS.VizieR/J/A+A/597/A25
- Title:
- IK Tau millimeter IRAM-30m line survey
- Short Name:
- J/A+A/597/A25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to investigate the physical and chemical properties of the molecular envelope of the oxygen-rich AGB star IK Tau. We carried out a millimeter wavelength line survey between ~79 and 356GHz with the IRAM-30m telescope. We analysed the molecular lines detected in IK Tau using the population diagram technique to derive rotational temperatures and column densities. We conducted a radiative transfer analysis of the SO_2_ lines, which also helped us to verify the validity of the approximated method of the population diagram for the rest of the molecules.
- ID:
- ivo://CDS.VizieR/J/A+A/562/A89
- Title:
- i light curve ans spectra of Hen2-11 central star
- Short Name:
- J/A+A/562/A89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed photometric study of the central star system of the planetary nebula Hen 2-11, selected for study because of its low-ionisation filaments and bipolar morphology - traits which have been strongly linked with central star binarity. Photometric monitoring with NTT-EFOSC2 reveals a highly irradiated, double-eclipsing, post-common-envelope system with a period of 0.609 d. Modelling of the lightcurve indicates that the nebular progenitor is extremely hot, while the secondary in the system is probably a K-type main sequence star. The chemical composition of the nebula is analysed, showing Hen 2-11 to be a medium-excitation non-Type I nebula. A simple photoionisation model is constructed determining abundance ratios of C/O and N/O which would be consistent with the common-envelope cutting short the AGB evolution of the nebular progenitor. The detection of a post-common-envelope binary system at the heart of Hen 2-11 further strengthens the link between binary progeny and the formation of axisymmetric planetary nebulae with patterns of low-ionisation filaments, clearly demonstrating their use as morphological indicators of central star binarity.
- 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.
