- ID:
- ivo://CDS.VizieR/J/MNRAS/451/4193
- Title:
- Fermi/non-Fermi blazars jet power and accretion
- Short Name:
- J/MNRAS/451/4193
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the relationship between jet power and accretion for Fermi and non-Fermi blazars. We also compare the relevant parameter. Our main results are: (i) Fermi and non-Fermi blazars have significant differences in red shift, black hole mass and broad line luminosity. (ii) Fermi blazars have a higher average core-dominance parameter than non-Fermi blazars, which suggests that Fermi blazars have a strong beaming effect. (iii) We find a significant correlation between broad line emission and jet power for Fermi and non-Fermi blazars, which suggests a direct tight connection between jet and accretion. (iv) The accretion and black hole mass may have a different contribution to jet power for Fermi and non-Fermi blazars.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/530/A72
- Title:
- Fermi sources with massive YSO associations
- Short Name:
- J/A+A/530/A72
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Massive protostars have associated bipolar outflows that can produce strong shocks when they interact with the surrounding medium. At these shocks, particles can be accelerated up to relativistic energies. Relativistic electrons and protons can then produce gamma-ray emission, as some theoretical models predict. To identify young galactic objects that may emit gamma rays, we crossed the Fermi First Year Catalog with some catalogs of known massive young stellar objects (MYSOs), early type stars, and OB associations, and we implemented Monte Carlo simulations to find the probability of chance coincidences. We obtained a list of massive MYSOs that are spatially coincident with Fermi sources.
- ID:
- ivo://CDS.VizieR/IX/60
- Title:
- Fermi superluminal sources
- Short Name:
- IX/60
- Date:
- 07 Mar 2022 07:19:31
- Publisher:
- CDS
- Description:
- Paper I (2019SCPMA..62l9811X): Active galactic nuclei (AGNs) have been attracting research attention due to their special observable properties. Specifically, a majority of AGNs are detected by Fermi-LAT missions, but not by Fermi-LAT, which raises the question of weather any differences exist between the two. To answer this issue, we compile a sample of 291 superluminal AGNs (189 FDSs and 102 non-FDSs) from available multi-wavelength radio, optical, and X-ray (or even {gamma}-ray) data and Doppler factors and proper motion ({mu}) (or apparent velocity ({beta}app)); calculated the apparent velocity from their proper motion, Lorentz factor ({GAMMA}), viewing angle ({phi}) and co-moving viewing angle ({phi}co) for the sources with available Doppler factor ({delta}); and performed some statistical analyses for both types. Our study indicated that (1) in terms of average values, FDSs have higher proper motions ({mu}), apparent velocities ({beta}_app_), Doppler factor ({delta}), Lorentz factor ({GAMMA}), and smaller viewing angle ({phi}). Nevertheless, there is no clear difference in co-moving viewing angles ({phi}_co_). The results reveal that FDSs show stronger beaming effect than non-FDSs. (2) In terms of correlations: 1) both sources show positive, mutually correlated fluxes, which become closer in de-beamed fluxes; 2) with respect to apparent velocities and {gamma}-ray luminosity, there is a tendency for the brighter sources to have higher velocities; 3) with regard to viewing angle and observed {gamma}-ray luminosity, log{phi}=-(0.23+/-0.04)logL{gamma}+(11.14+/-1.93), while for the co-moving viewing angle and the intrinsic {gamma}-ray luminosity, log{phi}_co_=(0.09+/-0.01)logL^in^_(gamma)_-(1.73+/-0.48). These correlations show that the luminous {gamma}-ray sources have smaller viewing angles and a larger co-moving viewing angle, which indicate a stronger beaming effect in {gamma}-ray emissions. Paper II (2020AN....341..462X): In our previous work in Xiao et al. (SCPMA, 2019, 62, 129811), we suggested that six superluminal sources could be {gamma}-ray candidates, and in fact, five of them have been confirmed in the fourth Fermi-LAT source catalog (4FGL). In this work, based on the 4FGL, we report a sample of 229 Fermi detected superluminal sources (FDSs), including 40 new FDSs and 62 non-FDSs. Thus, we believe that all superluminal sources should have {gamma}-ray emissions, and superluminal motion could also be a clue to detect {gamma}-ray emission from active galactic nuclei. We present a new approach of Doppler factor estimate through the study of the {gamma}-ray luminosity (L{gamma}) and of the viewing angle ({phi}). Paper III (2020A&C....3200387X): In this work, Machine Learning (ML) methods are used to efficiently identify the unassociated sources and the Blazar Candidate of Uncertain types (BCUs) in the Fermi-LAT Third Source Catalog (3FGL). The aims are twofold: (1) to distinguish the Active Galactic Nuclei (AGNs) from others (non-AGNs) in the unassociated sources; (2) to identify BCUs into BL Lacertae objects (BL Lacs) or Flat Spectrum Radio Quasars (FSRQs). Two dimensional reduction methods are presented to decrease computational complexity, where Random Forest (RF), Multilayer Perceptron (MLP) and Generative Adversarial Nets (GAN) are trained as individual models. In order to achieve better performance, the ensemble technique is further explored. It is also demonstrated that grid search method is of help to choose the hyperparameters of models and decide the final predictor, by which we have identified 748 AGNs out of 1010 unassociated sources, with an accuracy of 97.04%. Within the 573 BCUs, 326 have been identified as BL Lacs and 247 as FSRQs, with an accuracy of 92.13%.
- ID:
- ivo://CDS.VizieR/J/MNRAS/432/1294
- Title:
- Fermi unassociated sources ATCA observations
- Short Name:
- J/MNRAS/432/1294
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report results of the first phase of observations with Australia Telescope Compact Array (ATCA) at 5 and 9GHz of the fields around 411 {gamma}-ray sources with declinations less than +10{deg} detected with Fermi but marked as unassociated in the 2FGL catalogue. We have detected 424 sources with flux densities in a range of 2mJy to 6Jy in the fields of 283 {gamma}-ray sources within their position error ellipses drawn to cover the area of 99 per cent probability of their localisation. Of them, 146 objects were detected in both bands. We found 84 sources with spectral index flatter than -0.5 in our sample. The majority of detected sources are weaker than 100 mJy and for this reason were not found in previous surveys. Approximately 1/3 of our sample, 128 objects, have the probability of being associated by more than 10 times than the probability of being a background source found in the vicinity of a {gamma}-ray object by chance. We present the catalogue of positions of these sources, estimates of their flux densities and spectral indices when available.
6215. FEROS Public Spectra
- ID:
- ivo://org.gavo.dc/feros/q/ssa
- Title:
- FEROS Public Spectra
- Short Name:
- FEROS SSAP
- Date:
- 15 Aug 2024 15:16:58
- Publisher:
- The GAVO DC team
- Description:
- Spectra from FEROS spectrograph at La Silla's 1.5m telescope as obtained during commissioning and guaranteed time.
- ID:
- ivo://CDS.VizieR/J/A+A/554/A27
- Title:
- 2011fe spectrophotometric time series
- Short Name:
- J/A+A/554/A27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 32 epochs of optical (3300-9700{AA}) spectrophotometric observations of the nearby quintessential "normal" type Ia supernova (SN Ia) SN 2011fe in the galaxy M101, extending from -15 to +97d with respect to B-band maximum, obtained by the Nearby Supernova Factory collaboration. SN 2011fe is the closest ({mu}=29.04) and brightest (Bmax=9.94mag) SN Ia observed since the advent of modern large scale programs for the intensive periodic followup of supernovae. Both synthetic light curve measurements and spectral feature analysis attest to the normality of SN 2011fe. There is very little evidence for reddening in its host galaxy. The homogeneous calibration, intensive time sampling, and high signal-to-noise ratio of the data set make it unique. Thus it is ideal for studying the physics of SN Ia explosions in detail, and for furthering the use of SNe Ia as standardizable candles for cosmology.
- ID:
- ivo://CDS.VizieR/J/A+A/597/A74
- Title:
- FeSt 1-457 IRAM and PdBI maps
- Short Name:
- J/A+A/597/A74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Pre-stellar cores within molecular clouds provide the very initial conditions in which stars are formed. FeSt 1-457 is a prototypical starless core and the most chemically evolved among those isolated, embedded in the most pristine part of the Pipe nebula, the bowl. We use the IRAM 30m telescope and the PdBI to study the chemical and physical properties of the starless core FeSt 1-457 (Core 109) in the Pipe nebula. We fit the hyperfine structure of the N_2_H^+^ (1-0) IRAM 30m data. This allowed us to measure with high precision the velocity field, line widths and opacity and derive the excitation temperature and column density in the core. We used a modified Bonnor-Ebert sphere model adding a temperature gradient towards the center to fit the 1.2mm continuum emission and visual extinction maps. Using this model, we have estimated the abundances of the N_2_H^+^ and the rest of molecular lines detected in the 30GHz wide line survey performed at 3mm with IRAM 30m using ARTIST software.
- ID:
- ivo://CDS.VizieR/J/A+A/422/731
- Title:
- Fe X Benchmarking atomic data
- Short Name:
- J/A+A/422/731
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the first in a series of papers in which we benchmark recent atomic data available for astrophysical applications. We review various issues related to the completeness and accuracy of both theoretical and experimental data. In this paper, the available experimental and atomic data for Fe X (n=3 configurations) are reviewed and assessed. New collisional and radiative data are calculated to supplement published data. The radiative calculations are done with empirical adjustements that take into account observed wavelengths. Previous line identifications are also reviewed and assessed. Our approach focuses on the brightest spectral lines, and uses both wavelengths and line intensities to assess the line identifications on a quantitative basis. Although many previous line identifications are confirmed, some are rejected (e.g. the coronal line observed at 1582.35{AA}). We confirm previously suggested identifications (e.g. 257.262{AA},1028.02{AA}), and we present new ones, (e.g. the lines of the 3s^2^ 3p^4^ 3d-3s 3p^5^ 3d transition array). In addition, we highlight the presence of blends and we review which spectral lines are best for density diagnostics or for instrument calibration. The theoretical data (line intensities and level lifetimes) are benchmarked against well-calibrated spectroscopic observations of the solar corona and laboratory measurements. The agreement between theoretical and experimental data which we achieve with our new model ion is very good.
- ID:
- ivo://CDS.VizieR/J/A+A/427/763
- Title:
- FeX E1, E2, M1 and M2 transitions
- Short Name:
- J/A+A/427/763
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Energies of the 54 levels belonging to the (1s^2^2s^2^2p^6^) 3s^2^3p^5^, 3s3p^6^, 3s^2^3p^4^3d and 3s3p^5^3d configurations of FeX have been calculated using the GRASP code of Dyall et al. (1989, Comput. Phys. Commun, 55, 424). Additionally, radiative rates, oscillator strengths, and line strengths are calculated for all electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), and magnetic quadrupole (M2) transitions among these levels. Comparisons are made with results available in the literature, and the accuracy of the data is assessed. Our energy levels are estimated to be accurate to better than 3%, whereas results for other parameters are probably accurate to better than 20%. Additionally, the agreement between measured and calculated lifetimes is better than 10%.
- ID:
- ivo://CDS.VizieR/J/A+A/414/377
- Title:
- FeX-FeXVII fine-structure K-vacancy levels
- Short Name:
- J/A+A/414/377
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report extensive calculations of the decay properties of fine-structure K-vacancy levels in Fe X-Fe XVII. A large set of level energies, wavelengths, radiative and Auger rates, and fluorescence yields has been computed using three different standard atomic codes, namely Cowan's HFR, AUTOSTRUCTURE and the Breit-Pauli R-matrix package. This multi-code approach is used to the study the effects of core relaxation, configuration interaction and the Breit interaction, and enables the estimate of statistical accuracy ratings. The K-alpha and KLL Auger widths have been found to be nearly independent of both the outer-electron configuration and electron occupancy keeping a constant ratio of 1.53+/-0.06. By comparing with previous theoretical and measured wavelengths, the accuracy of the present set is determined to be within 2m{AA}. Also, the good agreement found between the different radiative and Auger data sets that have been computed allow us to propose with confidence an accuracy rating of 20% for the line fluorescence yields greater than 0.01. Emission and absorption spectral features are predicted finding good correlation with measurements in both laboratory and astrophysical plasmas.