- ID:
- ivo://CDS.VizieR/J/ApJ/841/76
- Title:
- Intrinsic far-IR SED of luminous AGNs
- Short Name:
- J/ApJ/841/76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The range of currently proposed active galactic nucleus (AGN) far-infrared templates results in uncertainties in retrieving host galaxy information from infrared observations and also undermines constraints on the outer part of the AGN torus. We discuss how to test and reconcile these templates. Physically, the fraction of the intrinsic AGN IR-processed luminosity compared with that from the central engine should be consistent with the dust-covering factor. In addition, besides reproducing the composite spectral energy distributions (SEDs) of quasars, a correct AGN IR template combined with an accurate library of star-forming galaxy templates should be able to reproduce the IR properties of the host galaxies, such as the luminosity-dependent SED shapes and aromatic feature strengths. We develop tests based on these expected behaviors and find that the shape of the AGN intrinsic far-IR emission drops off rapidly starting at ~20{mu}m and can be matched by an Elvis+ (1994, J/ApJS/95/1)-like template with a minor modification. Despite the variations in the near- to mid-IR bands, AGNs in quasars and Seyfert galaxies have remarkably similar intrinsic far-IR SEDs at {lambda}~20-100{mu}m, suggesting a similar emission character of the outermost region of the circumnuclear torus. The variations of the intrinsic AGN IR SEDs among the type-1 quasar population can be explained by the changing relative strengths of four major dust components with similar characteristic temperatures, and there is evidence for compact AGN-heated dusty structures at sub-kiloparsec scales in the far-IR.
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- ID:
- ivo://CDS.VizieR/J/ApJ/731/120
- Title:
- Intrinsic SN Ia light curves
- Short Name:
- J/ApJ/731/120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have constructed a comprehensive statistical model for Type Ia supernova (SN Ia) light curves spanning optical through near-infrared (NIR) data. A hierarchical framework coherently models multiple random and uncertain effects, including intrinsic supernova (SN) light curve covariances, dust extinction and reddening, and distances. An improved BayeSN Markov Chain Monte Carlo code computes probabilistic inferences for the hierarchical model by sampling the global probability density of parameters describing individual SNe and the population. We have applied this hierarchical model to optical and NIR data of 127 SNe Ia from PAIRITEL, CfA3, Carnegie Supernova Project, and the literature. We find an apparent population correlation between the host galaxy extinction AV and the ratio of total-to-selective dust absorption RV. For SNe with low dust extinction, A_V_<~0.4, we find R_V_~2.5-2.9, while at high extinctions, A_V_>~1, low values of R_V_<2 are favored. The NIR luminosities are excellent standard candles and are less sensitive to dust extinction. They exhibit low correlation with optical peak luminosities, and thus provide independent information on distances. The combination of NIR and optical data constrains the dust extinction and improves the predictive precision of individual SN Ia distances by about 60%. Using cross-validation, we estimate an rms distance modulus prediction error of 0.11mag for SNe with optical and NIR data versus 0.15mag for SNe with optical data alone. Continued study of SNe Ia in the NIR is important for improving their utility as precise and accurate cosmological distance indicators.
- ID:
- ivo://CDS.VizieR/J/A+A/361/641
- Title:
- Investigation of mass loss mechanism of LPVs
- Short Name:
- J/A+A/361/641
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to investigate the relations between the mass loss from pulsating red giants and quantities which can be obtained from observations, we have explored the behavior of theoretical models which treat the time-dependent hydrodynamics of circumstellar outflows, including a detailed treatment of the dust formation process. This approach, while ignoring effects such as a possible non-sphericity of the stellar atmospheres which are difficult to assess, accounts correctly for factors such as the grain formation and destruction which are crucial to the mass-loss mechanism. We built a grid of ~150 models covering a wide range of physical situations. This grid allows us to characterize the effects of different parameters, such as the stellar luminosity and temperature, the period and the amplitude of the pulsation, and the C/O element abundance ratio, on the behavior of AGB winds and on the rates of mass loss. We find two regimes for the stellar outflows.
- ID:
- ivo://CDS.VizieR/J/A+A/618/A4
- Title:
- IRC+10216 as a spectroscopic laboratory
- Short Name:
- J/A+A/618/A4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This work presents a detailed analysis of the laboratory and astrophysical spectral data available for ^28^SiC_2_, ^29^SiC_2_, ^30^SiC_2_, Si^13^CC, and Si_2_C. New data on the rotational lines of these species between 70 and 350GHz have been obtained with high spectral resolution (195kHz) with the IRAM 30m telescope in the direction of the circumstellar envelope IRC+10216. Frequency measurements can reach an accuracy of 50kHz for features observed with a good signal to noise ratio. From the observed astrophysical lines and the available laboratory data new rotational and centrifugal distortion constants have been derived for all the isotopologues of SiC_2_, allowing to predict their spectrum with high accuracy in the millimeter and submillimeter domains. Improved rotational and centrifugal distortion constants have also been obtained for disilicon carbide, Si_2_C. This work shows that observations of IRC+10216 taken with the IRAM 30m telescope, with a spectral resolution of 195kHz, can be used for any molecular species detected in this source to derive, or improve, its rotational constants. Hence, IRC+10216 in addition to be one the richest sources in molecular species in the sky, can also be used as a state-of-the-art spectroscopy laboratory in the millimeter and submillimeter domains.
- ID:
- ivo://CDS.VizieR/J/A+A/448/181
- Title:
- IR colours of AGB and post-AGB stars
- Short Name:
- J/A+A/448/181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With the advent of space missions, like SPITZER and ASTRO-F, with sensitive detectors in the near- and mid-infrared covering a reasonable field-of-view and having a good spatial resolution it will be possible to detect individual AGB stars in Local Group galaxies. The filters used by these missions are non-standard and different from mission to mission. In this paper the colours of mass-losing AGB and post-AGB stars are calculated in the broad-band filters of the SPITZER and ASTRO-F missions, as well as Bessell V,I and 2MASS J,H,K to connect these results to existing ground-based data. The models are calculated for carbon- and oxygen-rich chemistry and cover different effective temperatures and dust compositions.
- ID:
- ivo://CDS.VizieR/J/A+A/402/343
- Title:
- IR O I triplet, [O I] lines in F-K dwarfs/giants
- Short Name:
- J/A+A/402/343
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to investigate the formation of O I 7771-5 and [O I] 6300/6363 lines, extensive non-LTE calculations for neutral atomic oxygen were carried out for wide ranges of model atmosphere parameters, which are applicable to early-K through late-F halo/disk stars of various evolutionary stages. The formation of the triplet O I lines was found to be well described by the classical two-level-atom scattering model, and the non-LTE correction is practically determined by the parameters of the line-transition itself without any significant relevance to the details of the oxygen atomic model. This simplifies the problem in the sense that the non-LTE abundance correction is essentially determined only by the line-strength (W_{lambda}_), if the atmospheric parameters of Teff, logg, and {xi} are given, without any explicit dependence of the metallicity; thus allowing a useful analytical formula with tabulated numerical coefficients. On the other hand, our calculations lead to the robust conclusion that LTE is totally valid for the forbidden [O I] lines.
- ID:
- ivo://CDS.VizieR/J/ApJ/729/94
- Title:
- IR spectroscopy of PAH in 6-15{mu}m band
- Short Name:
- J/ApJ/729/94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Polycyclic aromatic hydrocarbon (PAH) growth and destruction are thought to proceed via the occasional incorporation of five- and seven-membered fused ring defects in the hexagonal carbon skeleton. Using density functional theory, this paper investigates the effect such five- and seven-membered fused ring defects have on the infrared spectra of ovalene (OV; C_32_H_14_), circumovalene (c-OV; C_66_H_20_), and circumcircumovalene (cc-OV; C_112_H_26_). The defects make only small changes to the overall infrared (IR) spectra, both in the mid-IR and in the far-IR, of these species. In addition to small shifts in the positions of the bands between the PAHs with and without defects, the most common effect of the defects is to increase the number of bands. Except for an anion with the Stone-Wales defect, all of the species studied have the C-C stretching band at 6.3um or at longer wavelengths, the position in Classes B and C astronomical PAH spectra. In the case of the Stone-Wales anion, the band falls at 6.20um, suggesting that further study of defects is probably worthwhile, as some PAHs with defects might be important in those sources (Class A) that show a C-C stretching band that falls near 6.2um.
- ID:
- ivo://CDS.VizieR/J/ApJ/663/320
- Title:
- IR-through-UV extinction curve
- Short Name:
- J/ApJ/663/320
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the IR-through-UV wavelength dependence of 328 Galactic interstellar extinction curves affecting normal, near-main-sequence B and late O stars. We derive the curves using a new technique that employs stellar atmosphere models in lieu of unreddened "standard" stars. Under ideal conditions, this technique is capable of virtually eliminating spectral mismatch errors in the curves. In general, it lends itself to a quantitative assessment of the errors and enables a rigorous testing of the significance of relationships between various curve parameters, regardless of whether their uncertainties are correlated.
- ID:
- ivo://CDS.VizieR/J/MNRAS/387/105
- Title:
- Isochrone database for single- and binary-star SSPs
- Short Name:
- J/MNRAS/387/105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We first presented an isochrone data base that can be widely used for stellar population synthesis studies and colour-magnitude diagram (CMD) fitting. The data base consists of the isochrones of both single-star and binary-star simple stellar populations (ss-SSPs and bs-SSPs). The ranges for the age and metallicity of populations are 0-15Gyr and 0.0001-0.03, respectively. All data are available for populations with two widely used initial mass functions (IMFs), that is, Salpeter IMF and Chabrier IMF. The uncertainty caused by the data base (about 0.81 per cent) is designed to be smaller than those caused by the Hurley code and widely used stellar spectra libraries (e.g. BaSeL 3.1) when it is used for stellar population synthesis. Based on the isochrone data base, we then built a rapid stellar population synthesis (RPS) model and calculated the high-resolution (0.03nm) integrated spectral energy distributions, Lick indices and colour indices for bs-SSPs and ss-SSPs. In particular, we calculated the UBVRIJHKLM colours, ugriz colours and some composite colours that consist of magnitudes on different systems. These colours are useful for disentangling the well-known stellar age-metallicity degeneracy according to our previous work. As an example for applying the isochrone data base for CMD fitting, we fitted the CMDs of two star clusters (M67 and NGC1868) and obtained their distance moduli, colour excesses, stellar metallicities and ages. The results showed that the isochrones of bs-SSPs are closer to those of real star clusters. It suggests that we should take the effects of binary interactions into account in stellar population synthesis. We also discussed on the limitations of the application of the isochrone data base and the results of the RPS model.
- ID:
- ivo://CDS.VizieR/J/ApJ/818/18
- Title:
- Jet angles and gamma-ray energetics estimations
- Short Name:
- J/ApJ/818/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a method to estimate the jet opening angles of long duration gamma-ray bursts (GRBs) using the prompt gamma-ray energetics and an inversion of the Ghirlanda relation, which is a correlation between the time-integrated peak energy of the GRB prompt spectrum and the collimation-corrected energy in gamma-rays. The derived jet opening angles using this method and detailed assumptions match well with the corresponding inferred jet opening angles obtained when a break in the afterglow is observed. Furthermore, using a model of the predicted long GRB redshift probability distribution observable by the Fermi Gamma-ray Burst Monitor (GBM), we estimate the probability distributions for the jet opening angle and rest-frame energetics for a large sample of GBM GRBs for which the redshifts have not been observed. Previous studies have only used a handful of GRBs to estimate these properties due to the paucity of observed afterglow jet breaks, spectroscopic redshifts, and comprehensive prompt gamma-ray observations, and we potentially expand the number of GRBs that can be used in this analysis by more than an order of magnitude. In this analysis, we also present an inferred distribution of jet breaks which indicates that a large fraction of jet breaks are not observable with current instrumentation and observing strategies. We present simple parameterizations for the jet angle, energetics, and jet break distributions so that they may be used in future studies.
