- ID:
- ivo://CDS.VizieR/J/MNRAS/415/1577
- Title:
- CoRoT 105288363 Blazhko modulation
- Short Name:
- J/MNRAS/415/1577
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the COnvection, ROtation and planetary Transits (CoRoT) star 105288363, a new Blazhko RR Lyrae star of type RRab (f0=1.7623d^-1^), observed with the CoRoT spacecraft during the second long run in the direction of the Galactic Centre (LRc02, time-base 145d). The CoRoT data are characterized by an excellent time-sampling and a low noise amplitude of 0.07mmag in the 2-12d^-1^ range and allow us to study not only the fine details of the variability of the star, but also long-term changes in the pulsation behaviour and the stability of the Blazhko cycle. We use, among other methods, standard Fourier analysis techniques and O-C diagrams to investigate the pulsational behaviour of the Blazhko star 105288363. In addition to the frequency pattern expected for a Blazhko RR Lyrae star, we find an independent mode (f1=2.984d^-1^) showing a f0/f1 ratio of 0.59 which is similar to that observed in other Blazhko RR Lyrae stars. The bump and hump phenomena are also analysed, with their variations over the Blazhko cycle. We carefully investigated the strong cycle-to-cycle changes in the Blazhko modulation (P_B_=35.6d), which seem to happen independently and partly diametrically in the amplitude and phase modulations. Furthermore, the phasing between the two types of modulations is found to change during the course of the observations.
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- ID:
- ivo://CDS.VizieR/J/A+A/565/A55
- Title:
- CoRoT 105906206 frequencies analysis
- Short Name:
- J/A+A/565/A55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Eclipsing binary systems with pulsating components allow determination of several physical parameters of the stars, such as mass and radius, that can be used to constrain the modeling of stellar interiors and evolution when combined with the pulsation properties. We present the results of the study of CoRoT 105906206, an eclipsing binary system with a pulsating component located in the CoRoT LRc02 field. The analysis of the CoRoT light curve was complemented by high-resolution spectra from the Sandiford at McDonald Observatory and FEROS at ESO spectrographs, which revealed a double-lined spectroscopic binary. We used an iterative procedure to separate the pulsation-induced photometric variations from the eclipse signals. First, a Fourier analysis was used to identify the significant frequencies and amplitudes due to pulsations. Second, after removing the contribution of the pulsations from the light curve we applied the PIKAIA genetic-algorithm approach to derive the best parameters for describing the system orbital properties.
- ID:
- ivo://CDS.VizieR/J/A+A/556/A87
- Title:
- CoRoT-100866999 frequency analysis
- Short Name:
- J/A+A/556/A87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The presence of g- and p-modes allows testing stellar models from the core to the envelope. Moreover, binarity in an eclipsing system constrains the physical parameters of the pulsating star. CoRot ID 100866999 is a relatively large-amplitude hybrid gamma Doradus-delta Scuti star with two clearly distinct frequency domains. The large number of detected frequencies allows a detailed study of the interaction between them. In addition, we can derive the fundamental parameters of both components from the study of the eclipsing light curve. After removing the eclipsing phases, we analyzed the data with the Period04 package up to a signal-to-noise ratio S/N=4. The light curve was then prewhitened with these oscillation frequencies to derive the fundamental parameters of the two components.
- ID:
- ivo://CDS.VizieR/J/A+A/552/A60
- Title:
- CoRoT 102918586 light curve and spectra
- Short Name:
- J/A+A/552/A60
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Pulsating stars in eclipsing binary systems are powerful tools to test stellar models. Binarity enables us to constrain the pulsating component physical parameters and this knowledge drastically improves the input physics for asteroseismic studies. The study of stellar oscillations then allows us to improve our understanding of stellar interiors and stellar evolution. The space mission CoRoT discovered several promising objects suitable for these studies. They were photometrically observed with unprecedented accuracy, but needed spectroscopic follow-up. A promising target was the relatively bright eclipsing system CoRoT 102918586, which turned out to be a double-lined spectroscopic binary and also showed clear evidence of Gamma Dor type pulsations. With the aim of combining the information from binarity and pulsation and fully exploiting the potential of CoRoT photometry we obtained phase resolved high-resolution spectroscopy with the Sandiford spectrograph at the McDonald 2.1m telescope and the FEROS spectrograph at the ESO 2.2m telescope. Spectroscopy yielded both the radial velocity curves and, after spectra disentangling, the component effective temperatures, metallicity, and line-of-sight projected rotational velocities. The CoRoT light curve was analyzed with an iterative procedure, devised to disentangle eclipses from pulsations. The eclipsing binary light curve analysis, combined with the spectroscopic results, provided an accurate determination of the system parameters, and the comparison with evolutionary models provided strict constraints on the system age. Finally, the residuals obtained after subtraction of the best fitting eclipsing binary model were analyzed to determine the pulsator properties. We achieved a complete and consistent description of the system. The primary star pulsates with typical gamma Dor frequencies and shows a splitting in period that is consistent with high order g-mode pulsations in a star of the corresponding physical parameters. The value of the splitting, in particular, is consistent with pulsations in l=1 modes.
- ID:
- ivo://CDS.VizieR/J/A+A/527/A146
- Title:
- CoRoT 0105288363 light curves
- Short Name:
- J/A+A/527/A146
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The CoRoT - Convection Rotation and Planetary Transits - space mission provides a unique opportunity to monitor RR Lyrae stars with excellent time-sampling, unprecedented photometric precision, and a long time base of 150 days. The pulsation characteristics of RR Lyrae stars rely on robust physics, but we still lack a firm quantitative understanding of the physical mechanisms driving the Blazhko modulation and the long-term changes in their pulsation behavior. We use the high- precision space data of an unknown RR Lyrae star CoRoT ID 0105288363 observed during a second long run centered on the Galaxy -LRc02-, to improve our understanding of the pulsation properties of RR Lyrae stars.
- ID:
- ivo://CDS.VizieR/J/A+A/510/A39
- Title:
- CoRoT light curves of V1127 Aql
- Short Name:
- J/A+A/510/A39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The CoRoT space mission - Convection Rotation and Planetary Transits - is a great opportunity for monitoring stars with excellent time-sampling and unprecedented photometric precision for up to 150days. As an important benefit, high-quality RR Lyrae light curves are obtained with a quasi-uninterrupted coverage over several pulsation and Blazhko cycles. The Blazhko effect in RR Lyrae stars is an unsolved problem of astrophysics. We used the high-precision space data to contribute with more precise knowledge to clear up the possible physical processes behind the phenomenon. We applied different period finding techniques including Period04, MuFrAn, PDM and SigSpec. Amplitude and phase modulation were investigated by an analytical function method as well as with the traditional O-C diagrams. The Blazhko modulation frequency is directly detected in the spectrum, as well as its first and second harmonics. It shows the non-linear nature of the Blazhko modulation. Besides the triplets, further higher-order modulation side peaks appear around the pulsation frequency as quintuplet, septuplet, nonuplet, undecaplet, tredecaplet, quindecaplet and septdecaplet structures. Additional frequencies, not belonging to the classical multiplet structures, are detected, and their linear combinations with the fundamental radial mode. We interpret these additional terms as non-radial modes. During the five consecutive Blazhko cycles, there is a shift of the maximum phase around 0.011 pulsation phase which is likely the consequence of a long term modulation.
- ID:
- ivo://CDS.VizieR/J/MNRAS/465/2120
- Title:
- Correcting CIV-based virial black hole masses
- Short Name:
- J/MNRAS/465/2120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The CIV{lambda}{lambda}1498,1501 broad emission line is visible in optical spectra to redshifts exceeding z~5. CIV has long been known to exhibit significant displacements to the blue and these 'blueshifts' almost certainly signal the presence of strong outflows. As a consequence, single-epoch virial black hole (BH) mass estimates derived from CIV velocity widths are known to be systematically biased compared to masses from the hydrogen Balmer lines. Using a large sample of 230 high-luminosity (L_Bol_=10^45.5^-10^48^erg/s), redshift 1.5<z<4.0 quasars with both CIV and Balmer line spectra, we have quantified the bias in CIV BH masses as a function of the CIV blueshift. CIV BH masses are shown to be a factor of 5 larger than the corresponding Balmer-line masses at C IV blueshifts of 3000km/s and are overestimated by almost an order of magnitude at the most extreme blueshifts, ?=5000km/s. Using the monotonically increasing relationship between the CIV blueshift and the mass ratio BH(CIV)/BH(H{alpha}), we derive an empirical correction to all CIV BH masses. The scatter between the corrected CIV masses and the Balmer masses is 0.24dex at low CIV blueshifts (~0km/s) and just 0.10dex at high blueshifts (~3000km/s), compared to 0.40dex before the correction. The correction depends only on the CIV line properties - i.e. full width at half-maximum and blueshift - and can therefore be applied to all quasars where CIV emission line properties have been measured, enabling the derivation of unbiased virial BH-mass estimates for the majority of high-luminosity, high-redshift, spectroscopically confirmed quasars in the literature.
- ID:
- ivo://CDS.VizieR/J/ApJ/887/5
- Title:
- COS CGM compendium (CCC). III. z<=1 Ly{alpha} syst.
- Short Name:
- J/ApJ/887/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We characterize the metallicities and physical properties of cool, photoionized gas in a sample of 152 z<=1 strong Ly{alpha} forest systems (SLFSs, absorbers with 15<logN_HI_<16.2). The sample is drawn from our Cosmic Origins Spectrograph (COS) circumgalactic medium compendium (CCC), an ultraviolet survey of HI-selected circumgalactic gas around z<=1 galaxies that targets 261 absorbers with 15<logN_HI_<19. We show that the metallicity probability distribution function of the SLFSs at z<=1 is unimodal, skewed to low metallicities with a mean and median of [X/H]=-1.47 and -1.18dex. Very metal-poor gas with [X/H]{<}-1.4 represents about half of the population of absorbers with 15<logN_HI_<=18, while it is rare at higher N_HI_. Thus, there are important reservoirs of primitive (though not pristine) diffuse ionized gas around z<=1 galaxies. The photoionized gas around z<=1 galaxies is highly inhomogeneous based on the wide range of metallicities observed (-3<=[X/H]<=+0.4) and the fact that there are large metallicity variations (factors of 2 to 25) for most of the closely spaced absorbers ({Delta}v<=300km/s) along the same sightlines. These absorbers show a complex evolution with redshift and HI column density, and we identify subtle cosmic evolution effects that affect the interpretation of metallicity distributions and comparison with other absorber samples. We discuss the physical conditions and cosmic baryon and metal budgets of the CCC absorbers. Finally, we compare the CCC results to recent cosmological zoom simulations and explore the origins of the 15<logN_HI_<19 absorbers within the Evolution and Assembly of GaLaxies and their Environments (EAGLE) high-resolution simulations.
- ID:
- ivo://CDS.VizieR/J/ApJ/820/66
- Title:
- Cosmic evolution of long gamma-ray burst luminosity
- Short Name:
- J/ApJ/820/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The cosmic evolution of gamma-ray burst (GRB) luminosity is essential for revealing the GRB physics and for using GRBs as cosmological probes. We investigate the luminosity evolution of long GRBs with a large sample of 258 Swift/BAT GRBs. By describing the peak luminosity evolution of individual GRBs as L_p_{prop.to}(1+z)^k^, we get k=1.49+/-0.19 using the nonparametric {tau} statistics method without considering observational biases of GRB trigger and redshift measurement. By modeling these biases with the observed peak flux and characterizing the peak luminosity function of long GRBs as a smoothly broken power law with a break that evolves as L_b_{prop.to}(1+z)^kb^, we obtain k_b_=1.14^+0.99^_-0.47_ through simulations based on the assumption that the long GRB rate follows the star formation rate incorporating the cosmic metallicity history. The derived k and k_b_ values are systematically smaller than those reported in previous papers. By removing the observational biases of the GRB trigger and redshift measurement based on our simulation analysis, we generate mock complete samples of 258 and 1000 GRBs to examine how these biases affect the {tau} statistics method. We get k=0.94+/-0.14 and k=0.80+/-0.09 for the two samples, indicating that these observational biases may lead to overestimating the k value. With the large uncertainty of k_b_ derived from our simulation analysis, one cannot even convincingly argue for a robust evolution feature of the GRB luminosity.
- ID:
- ivo://CDS.VizieR/J/A+A/631/A40
- Title:
- Cosmic Horseshoe (J1148+1930) Ha and OIII spectra
- Short Name:
- J/A+A/631/A40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed analysis of the inner mass structure of the Cosmic Horseshoe (J1148+1930) strong gravitational lens system observed with the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3). In addition to the spectacular Einstein ring, this systems shows a radial arc. We obtained the redshift of the radial arc counter image z_s,r_=1.961+/-0.001 from Gemini observations. To disentangle the dark and luminous matter, we consider three different profiles for the dark matter distribution: a power-law profile, the NFW, and a generalized version of the NFW profile. For the luminous matter distribution, we base it on the observed light distribution that is fitted with three components: a point mass for the central light component resembling an active galactic nucleus, and the remaining two extended light components scaled by a constant M/L. To constrain the model further, we include published velocity dispersion measurements of the lens galaxy and perform a self-consistent lensing and axisymmetric Jeans dynamical modeling. Our model fits well to the observations including the radial arc, independent of the dark matter profile. Depending on the dark matter profile, we get a dark matter fraction between 60% and 70%. With our composite mass model we find that the radial arc helps to constrain the inner dark matter distribution of the Cosmic Horseshoe independently of the dark matter profile.
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