- ID:
- ivo://CDS.VizieR/J/other/NewA/36.32
- Title:
- V441 Lac VRI light curves
- Short Name:
- J/other/NewA/36.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first multi-color VRI CCD light curves of a short-period eclipsing binary star v441 Lac in this paper. We obtained our light curves on Oct. 4 and 8, 2013 at Xinglong station of National Astronomical Observatories, China. We updated the ephemeris of V441 Lac based on three new minima derived by our new observational data together with previously available light curve minima. By fitting the O-C (observed minus calculated) values of the minima, we found that the orbital period of V441 Lac exhibits an increasing trend of View the dP/dt=5.67(0.35)x10^-7^days/year, which might be explained by mass transfer from the secondary component to the primary one, or angular momentum exchange by magnetic activities. We also obtained the photometric orbital parameters with the Wilson & Devinney program. Our final result shows that the V441 Lac system is a semi-detached binary with the secondary component filling roche lobe.
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- ID:
- ivo://CDS.VizieR/J/ApJS/234/24
- Title:
- VLA 33GHz obs. of star-forming regions
- Short Name:
- J/ApJS/234/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 33GHz imaging for 112 pointings toward galaxy nuclei and extranuclear star-forming regions at ~2" resolution using the Karl G. Jansky Very Large Array (VLA) as part of the Star Formation in Radio Survey. A comparison with 33GHz Robert C. Byrd Green Bank Telescope single-dish observations indicates that the interferometric VLA observations recover 78%+/-4% of the total flux density over 25" regions (~kpc scales) among all fields. On these scales, the emission being resolved out is most likely diffuse non-thermal synchrotron emission. Consequently, on the ~30-300pc scales sampled by our VLA observations, the bulk of the 33GHz emission is recovered and primarily powered by free-free emission from discrete HII regions, making it an excellent tracer of massive star formation. Of the 225 discrete regions used for aperture photometry, 162 are extranuclear (i.e., having galactocentric radii rG>=250pc) and detected at >3{sigma} significance at 33GHz and in H{alpha}. Assuming a typical 33GHz thermal fraction of 90%, the ratio of optically-thin 33GHz to uncorrected H{alpha} star formation rates indicates a median extinction value on ~30-300pc scales of A_H{alpha}_~1.26+/-0.09mag, with an associated median absolute deviation of 0.87mag. We find that 10% of these sources are "highly embedded" (i.e., A_H{alpha}_>~3.3mag), suggesting that on average, HII regions remain embedded for <~1Myr. Finally, we find the median 33GHz continuum-to-H{alpha} line flux ratio to be statistically larger within rG<250pc relative to the outer disk regions by a factor of 1.82+/-0.39, while the ratio of 33GHz to 24{mu}m flux densities is lower by a factor of 0.45+/-0.08, which may suggest increased extinction in the central regions.
- ID:
- ivo://CDS.VizieR/J/AJ/110/1959
- Title:
- VLA survey of Abell clusters. V.
- Short Name:
- J/AJ/110/1959
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a program of optical imaging of 265 radio galaxies in rich clusters. Using isophotal surface photometry, we investigate the optical properties such as the morphology, surface-brightness profiles, surface-brightness/size relationships, ellipticities, and the frequency of nonelliptical isophotes. The results are compared to a "normal" nonradio-selected sample of elliptical galaxies from the same clusters. The goal is to determine if the parent population of FR I radio galaxies can be distinguished optically from radio-quiet galaxies. The results of the analysis are that cluster ellipticals are a very homogeneous class of objects. The optical properties are consistent with a one-parameter family, where the optical luminosity is the fundamental parameter. In all tests considered, radio-loud FR I galaxies cannot be distinguished optically from radio-quiet galaxies selected from the same environment. The local density of nearby companions (<20kpc) and the frequency of morphological peculiarities or tidal interactions are not statistically different between the radio-loud and quiet samples. There is some suggestion from comparison to published samples of non-cluster radio galaxies, that the cluster environment is not condusive to long-lived tidal interactions, and that such events may be more important to galaxy evolution in poor groups and lower density environments. Such events appear to have little influence on the formation of FR I radio galaxies in rich clusters. The results are consistent with the idea that all elliptical galaxies may at some time (or many times) contain powerful (FR I) radio sources.
7924. VLA survey of CDF-S. II.
- ID:
- ivo://CDS.VizieR/J/ApJS/179/95
- Title:
- VLA survey of CDF-S. II.
- Short Name:
- J/ApJS/179/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the optical and infrared identifications of the 266 radio sources detected at 20cm with the Very Large Array in the Chandra Deep Field-South. Using deep i-band Advanced Camera for Surveys, R-band Wide Field Imager, K-band SOFI NTT, K-band ISAAC VLT and Spitzer imaging data, we are able to find reliable counterparts for 254 (~95%) VLA sources. Twelve radio sources remain unidentified, and three of them are "empty fields". Using literature and our own data we are able to assign redshifts to 186 (~70%) radio sources: 108 are spectroscopic redshifts and 78 are reliable photometric redshifts. Based on the rest-frame colors and morphological distributions of the host galaxies, we find evidences for a change in the submillijansky radio source population: (1) above ~0.08mJy early-type galaxies are dominating and (2) at flux densities below ~0.08mJy, starburst galaxies become dominant.
- ID:
- ivo://CDS.VizieR/J/ApJ/899/141
- Title:
- VLBA observations of the AGN TXS 0128+554
- Short Name:
- J/ApJ/899/141
- Date:
- 14 Mar 2022 07:07:50
- Publisher:
- CDS
- Description:
- We have carried out a Chandra X-ray and multifrequency radio Very Long Baseline Array study of the active galactic nucleus (AGN) TXS0128+554, which is associated with the Fermi {gamma}-ray source 4FGLJ0131.2+5547. The AGN is unresolved in a target 19.3ks Chandra image, and its spectrum is well fit by a simple absorbed power-law model, with no distinguishable spectral features. Its relatively soft X-ray spectrum compared to other compact symmetric objects (CSOs) may be indicative of a thermal emission component, for which we were able to obtain an upper temperature limit of kT=0.08keV. The compact radio morphology and measured advance speed of 0.32c{+/-}0.07c indicate a kinematic age of only 82yr{+/-}17yr, placing TXS0128+554 among the youngest members of the CSO class. The lack of compact, inverted spectrum hotspots and an emission gap between the bright inner jet and outer radio lobe structure indicate that the jets have undergone episodic activity, and were relaunched a decade ago. The predicted {gamma}-ray emission from the lobes, based on an inverse Compton-emitting cocoon model, is three orders of magnitude below the observed Fermi-LAT flux. A comparison to other Fermi-detected and non-Fermi-detected CSOs with redshift z<0.1 indicates that the {gamma}-ray emission likely originates in the inner jet/core region, and that nearby, recently launched AGN jets are primary candidates for detection by the Fermi-LAT instrument.
7926. V light curve of AzV 73
- ID:
- ivo://CDS.VizieR/J/A+A/380/258
- Title:
- V light curve of AzV 73
- Short Name:
- J/A+A/380/258
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A CCD V light curve for the eclipsing binary star AzV 73 is presented. This new photometric observations are analysed together with previously published CCD I photometry from Udalski et al. (1998AcA....48..563U) and spectrographic data from Niemela & Bassino (1994ApJ...437..332N), by means of the Wilson-Devinney code. It is found that this system is semi-detached, with an orbital inclination of roughly 86{deg} and a separation of 42R_{sun}_. The sizes and masses are R_1_=11.53 +/-0.5R_{sun}_, M_1_=25.26+/-0.7M_{sun}_, and R_2_=15.46+/-0.4R_{sun}_, M_2_=21.96+/-0.8M_{sun}_ for the primary and secondary components, respectively.
- ID:
- ivo://CDS.VizieR/J/AJ/145/45
- Title:
- V light curve of BZ Camelopardalis
- Short Name:
- J/AJ/145/45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Sequences of spectra of the nova-like cataclysmic variable (CV) BZ Cam were acquired on nine nights in 2005-2006 in order to study the time development of episodes of wind activity known to occur frequently in this star. We confirm the results of Ringwald & Naylor that the P-Cygni absorption components of the lines mostly evolve from higher expansion velocity to lower velocity as an episode progresses. We also commonly find blueshifted emission components in the H{alpha} line profile, whose velocities and durations strongly suggest that they are also due to the wind. Curiously, Ringwald & Naylor reported common occurrences of redshifted H{alpha} emission components in their BZ Cam spectra. We have attributed these emission components in H{alpha} to occasions when gas concentrations in the bipolar wind (both front side and back side) become manifested as emission lines as they move beyond the disk's outer edge. We also suggest, based on changes in the P-Cygni profiles during an episode, that the progression from larger to smaller expansion velocities is due to the higher velocity portions of a wind concentration moving beyond the edge of the continuum light of the disk first, leaving a net redward shift of the remaining absorption profile. We derive a new orbital ephemeris for BZ Cam, using the radial velocity of the core of the HeI{lambda}5876 line, finding P=0.15353(4). Using this period, the wind episodes in BZ Cam are found to be concentrated near the inferior conjunction of the emission line source. This result helps confirm that the winds in nova-like CVs are often phase dependent, in spite of the puzzling implication that such winds lack axisymmetry. We argue that the radiation-driven wind in BZ Cam receives an initial boost by acting on gas that has been lifted above the disk by the interaction of the accretion stream with the disk, thereby imposing flickering timescales onto the wind events, as well as leading to an orbital modulation of the wind due to the non-axisymmetric nature of the stream/disk interaction. Simultaneous photometry and spectroscopy were acquired on three nights in order to test the possible connection between flickering continuum light and the strength of the front-side wind. We found strong agreement on one night, some agreement on another, and no agreement on the third. We suggest that some flickering events lead to only back-side winds which will not have associated P-Cygni profiles.
7928. V light curve of RW Aur
- ID:
- ivo://CDS.VizieR/J/AJ/146/112
- Title:
- V light curve of RW Aur
- Short Name:
- J/AJ/146/112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- RW Aur A is a classical T Tauri star, believed to have undergone a reconfiguration of its circumstellar environment as a consequence of a recent flyby of its stellar companion, RW Aur B. This interaction stripped away part of the circumstellar disk of RW Aur A, leaving a tidally disrupted "arm" and a short truncated circumstellar disk. We present photometric observations of the RW Aur system from the Kilodegree Extremely Little Telescope survey showing a long and deep dimming that occurred from 2010 September until 2011 March. The dimming has a depth of ~2mag, a duration of ~180 days, and was confirmed by archival observations from American Association of Variable Star Observers. We suggest that this event is the result of a portion of the tidally disrupted disk occulting RW Aur A, specifically a fragment of the tidally disrupted arm. The calculated transverse linear velocity of the occulter is in excellent agreement with the measured relative radial velocity of the tidally disrupted arm. Using simple kinematic and geometric arguments, we show that the occulter cannot be a feature of the RW Aur A circumstellar disk, and we consider and discount other hypotheses. We also place constraints on the thickness and semimajor axis of the portion of the arm that occulted the star.
- ID:
- ivo://CDS.VizieR/J/A+A/486/505
- Title:
- V light curve of SDSS J080434.20+510349.2
- Short Name:
- J/A+A/486/505
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed a new cataclysmic variable (CV) SDSS J080434.20+510349.2 to study the origin of long-term variability found in its light curve. Multi-longitude, time-resolved, photometric observations were acquired to analyze this uncommon behavior, which has been found in two newly discovered CVs. This study of SDSS J080434.20+510349.2 concerns primarily the understanding of the nature of the observed, double-humped, light curve and its relation to a cyclic brightening that occurs during quiescence. The observations were obtained early in 2007, when the object was at about V~17.1, about 0.4mag brighter than the pre-outburst magnitude. The light curve shows a sinusoidal variability with an amplitude of about 0.07mag and a periodicity of 42.48min, which is half of the orbital period of the system. We observed in addition two "mini-outbursts" of the system of up to 0.6mag, which have a duration of about 4days each. The "mini-outburst" has a symmetric profile and is repeated in approximately every 32days. Subsequent monitoring of the system shows a cyclical behavior of such "mini-outbursts" with a similar recurrence period. The origin of the double-humped light curve and the periodic brightening is discussed in the light of the evolutionary state of SDSS J080434.20+510349.2.
- ID:
- ivo://CDS.VizieR/J/A+A/394/943
- Title:
- V light curve of V567 Oph
- Short Name:
- J/A+A/394/943
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present differential CCD photometry for the high-amplitude delta Scuti star V567 Ophiuchi obtained in the Johnson V-band. It was observed on 15 nights in two consecutive years in order to resolve the long-standing ambiguity related to its secondary period. A frequency analysis of almost 5000 individual single-filtered measurements resulted in two independent frequencies (f_1_=6.6879c/d and f_2_=11.8266c/d) with a ratio of f_1_/f_2_=0.565. The presented photometric data are differential magnitudes relative to the comparison star C_1_ (GSC 00417-01714) from Powell et al. (1990PASP..102.1131P)
