We present the development of software to control the multichannel image acquisition process and the design of an external timing module (ETM) for the OPTICAM system (Castro et al., 2019). The ETM is ...used to generate high-speed synchronized pulses for OPTICAM’s three different sCMOS cameras and is based on an ESP32-S2 micro-controller. The graphical user interface (GUI) of this instrument is also described, which allows users to enter the configuration parameters of the observations and execute actions such as starting and stopping image acquisition sequences or initializing cameras. 3 mini PCs are in charge of reading each one of the cameras, respectively. The software and hardware tools presented here have been successfully implemented at the Observatorio Astronómico Nacional (OAN-SPM), Mexico. By analyzing the recorded image sequences, it is possible to perform high-precision multi-channel photometric measurements of astrophysical objects that exhibit high temporal variability, revealing information about periodicities, inter-band delays, and quasi-periodic oscillations.
Bi-site time-series photometric and high-resolution spectroscopic observations were made for the double-mode high-amplitude δ Scuti star VX Hya. The fundamental frequency f0 = 4.4763 c days−1, the ...first overtone f1 = 5.7897 c days−1, and 23 harmonics and linear combinations of f0 and f1 are detected by pulsation analysis. From the spectroscopic data, we get Fe/H = −0.2 0.1 dex. The period change rate of the fundamental mode is obtained by using the Fourier-phase diagram method, which gives the value of . With these results from the observations, we perform theoretical explorations with the stellar evolution code MESA, and constrain the models by fitting f0, f1, and (1/P0)(dP0/dt) within 3 deviations. The results show that the period change of VX Hya could be ascribed to the evolutionary effect. The stellar parameters of VX Hya could be derived as: the mass 2.385 0.025 M , the luminosity log(L/L ) = 1.93 0.02, and the age (4.43 0.13) × 108 years. VX Hya is found to locate at the post-main-sequence stage with a helium core and a hydrogen-burning shell on the H-R diagram.
We present B, V, Rc and Ic light curves of four contact binary systems and one semi-detached system. New observations confirm and revise the short-period (0.22–0.25d) of the systems and that all the ...couple of stars belong to the spectral type K. In J105924 and J164349 a third light was found while the shape of the light curves of four systems (excluding J105924) suggest the presence of inhomogeneities on the surface of one component which confirms that the systems are active. Also they are observed at low orbital inclination i∈ (41°, 62°). Temperature differences range is ΔT∈(4,640)K and mass ratios q∈(0.20, 0.75). Absolute parameters are estimated using statistical diagrams. Systems follow the general pattern of the relative subtype of W Ursae Majoris systems. The sum of the component masses of four systems is below the mass limit of 1.0 – 1.2M☉ assumed for the known contact binary stars, this tells us that they belong to the class low mass contact binaries.
The results of our study of the eclipsing binary systems AF LMi, CzeV188 and CRTS J073333.0+302556 based on new CCD B, V, RC, IC complete light curves, are here presented. The short periods of these ...systems are confirmed and revised. The light curves were modeled using the latest version of the WilsonDevinney code and, as a result, we found that AF LMi (G3+G9) and CzeV188 (K0+K1) are W UMa-type contact binary systems belonging to the W subclass, showing a shallow degree of fill-out with components in good thermal contact. CRTS J073333.0+302556 is a detached binary system composed by a late dwarf (K8) and an M6 dwarf spectral type components. The asymmetries of the light curves were accounted for with a spot on the surface of one of the component. The absolute elements of the three objects were estimated.
Motivated by the shape of the halo occupation distribution (HOD) of X-ray selected AGNs in the COSMOS field recently inferred by Allevato et al., we investigated the HOD properties of moderate X-ray ...luminosity active galactic nuclei (mXAGNs) using a simple model based on the merging activity between dark matter halos (DMHs) in a ΛCDM cosmology. The HODs and number densities of the simulated mXAGNs at z = 0.5, under the above scenarios were compared with the results of Allevato et al. We found that the simulated HODs of major and minor mergers, and the observed HODs of mXAGNs are consistent. Our main result is that minor mergers, contrary to what one might expect, can play an important role in the activity of mAGNs.
We study the distribution of intragroup dark matter in small groups of dark matter galaxy size halos in a ACDM cosmology. These groups are identified using a physical criterion and may be an ...appropriate representation of small galaxy groups. We quantify the amount of intra-group dark matter and characterize its distribution. We find that compact associations of halos, as well as intermediate and loose groups, have rather fiat intragroup dark matter profiles, with logarithmic slopes of γ ≈ 0 and ≈ -0.2, respectively. Hence, the intra-group dark matter of these halo systems does not follow the same cuspy tendency of galactic halos. In intermediate and loose associations of galaxy-size halos, the intragroup matter tends to be ≲ 50% of the total mass of the group, while in compact associations it is ≲ 20% of the mass within their group radius.
Motivated by recent inferred form of the halo occupation distribution (HOD)
of X-ray selected AGNs, in the COSMOS field by Allevato et al. (2012), we
investigate the HOD properties of moderate X-ray ...luminosity Active Galactic
Nuclei (mXAGNs) using a simple model based on merging activity between dark
matter halos (DMHs) in a $\Lambda$-CDM cosmology. The HODs and number densities
of the simulated mXAGNs at $z=0.5$, under the above scenarios to compare with
Allevato et al. (2012) results. We find that the simulated HODs of major and
minor mergers, and the observed for mXAGNs are consistent among them. Our main
result is that minor mergers, contrary to what one might expect, can play an
important role in activity mAGNs.
Motivated by recent inferred form of the halo occupation distribution (HOD) of X-ray selected AGNs, in the COSMOS field by Allevato et al. (2012), we investigate the HOD properties of moderate X-ray ...luminosity Active Galactic Nuclei (mXAGNs) using a simple model based on merging activity between dark matter halos (DMHs) in a \(\Lambda\)-CDM cosmology. The HODs and number densities of the simulated mXAGNs at \(z=0.5\), under the above scenarios to compare with Allevato et al. (2012) results. We find that the simulated HODs of major and minor mergers, and the observed for mXAGNs are consistent among them. Our main result is that minor mergers, contrary to what one might expect, can play an important role in activity mAGNs.
Bi-site time-series photometric and high-resolution spectroscopic observations were made for the double-mode high-amplitude \(\delta\) Scuti star VX\ Hya. The fundamental frequency \(f_{0}=4.4763\ ...\rm{c\ days^{-1}}\), the first overtone \(f_{1}=5.7897\ \rm{c\ days^{-1}}\) and 23 harmonics and linear combinations of \(f_{0}\) and \(f_{1}\) are detected by pulsation analysis. From the spectroscopic data, we get \(\rm{Fe/H = -0.2\pm0.1\ dex}\). The period change rate of the fundamental mode is obtained by using the Fourier-phase diagram method, which gives the value of \((1/P_{0})(dP_{0}/dt)=(1.81\pm0.09) \times 10^{-7}\ \rm{yr}^{-1}\). With these results from the observations, we perform theoretical explorations with the stellar evolution code MESA, and constrain the models by fitting \(f_{0}\), \(f_{1}\), and \((1/P_{0})(dP_{0}/dt)\) within \(3\sigma\) deviations. The results show that the period change of VX\ Hya could be ascribed to the evolutionary effect. The stellar parameters of VX\ Hya could be derived as: the mass \(2.385\pm0.025\ M_{\odot}\), the luminosity \(\log(L/L_{\odot})=1.93\pm0.02\) and the age \((4.43\pm0.13)\times 10^8\) years. VX\ Hya is found to locate at the post-main-sequence stage with a helium core and a hydrogen-burning shell on the H\({-}\)R diagram.
The Astrophysical Journal, 861:96 (12pp), 2018 July 10 Bi-site time-series photometric and high-resolution spectroscopic
observations were made for the double-mode high-amplitude $\delta$ Scuti star
...VX\ Hya. The fundamental frequency $f_{0}=4.4763\ \rm{c\ days^{-1}}$, the first
overtone $f_{1}=5.7897\ \rm{c\ days^{-1}}$ and 23 harmonics and linear
combinations of $f_{0}$ and $f_{1}$ are detected by pulsation analysis. From
the spectroscopic data, we get $\rm{Fe/H = -0.2\pm0.1\ dex}$. The period
change rate of the fundamental mode is obtained by using the Fourier-phase
diagram method, which gives the value of $(1/P_{0})(dP_{0}/dt)=(1.81\pm0.09)
\times 10^{-7}\ \rm{yr}^{-1}$. With these results from the observations, we
perform theoretical explorations with the stellar evolution code MESA, and
constrain the models by fitting $f_{0}$, $f_{1}$, and $(1/P_{0})(dP_{0}/dt)$
within $3\sigma$ deviations. The results show that the period change of VX\ Hya
could be ascribed to the evolutionary effect. The stellar parameters of VX\ Hya
could be derived as: the mass $2.385\pm0.025\ M_{\odot}$, the luminosity
$\log(L/L_{\odot})=1.93\pm0.02$ and the age $(4.43\pm0.13)\times 10^8$ years.
VX\ Hya is found to locate at the post-main-sequence stage with a helium core
and a hydrogen-burning shell on the H${-}$R diagram.
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