- 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.
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Search Results
7942. 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.
7944. 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)
7947. V light curve of WR 123
- ID:
- ivo://CDS.VizieR/J/A+A/530/A151
- Title:
- V light curve of WR 123
- Short Name:
- J/A+A/530/A151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- What is the origin of the large-amplitude variability in Wolf-Rayet WN8 stars in general and WR123 in particular? A dedicated spectroscopic campaign targets the ten-hour period previously found in the high-precision photometric data obtained by the MOST satellite. In June-August 2003 we obtained a series of high signal-to-noise, mid-resolution spectra from several sites in the {lambda}{lambda}4000-6940{AA} domain. We also followed the star with occasional broadband (Johnson V) photometry. The acquired spectroscopy allowed a detailed study of spectral variability on timescales from ~5 minutes to months.
7948. V light curve of WR29
- ID:
- ivo://CDS.VizieR/J/A+A/506/1269
- Title:
- V light curve of WR29
- Short Name:
- J/A+A/506/1269
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- WR 29 is a known WN7h+O double-lined binary system with a rather short period (3.164-days). We search for light variations to determine the inclination of the system and thus the absolute masses of both components. We observed photometrically the field of WR 29 between December, 2002 and February, 2006. We find that the V light of WR 29 varies in phase with the spectroscopic period of 3.16412-days, presenting two minima corresponding to the conjunctions of the binary components. Numerical models fitted to the light curve indicate an orbital inclination of about 44{deg}, and masses of 53M_{sun}_ and 42M_{sun}_ for the O- and WN-type components, respectively.
7949. V light curves of EK Dra
- ID:
- ivo://CDS.VizieR/J/A+A/440/735
- Title:
- V light curves of EK Dra
- Short Name:
- J/A+A/440/735
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse photometric observations of the young active dwarf EK Dra, spanning altogether 21 years, and including previously unpublished data. The data in Table 2 was observed at the Fairbourn Observatory in southern Arizona using Amadeus, a 0.75m automatic photoelectric telescope (APT) of the University of Vienna. Amadeus is optimised for red wavelengths with an EMI-9828 tube and Johnson-Cousins V(RI)_C_ filters. Differential V magnitudes are variable (EK Dra) - comparison (HD 129390) and check (HD 129798) - comparison (HD 129390). HD 129390 Vmag=7.567
- ID:
- ivo://CDS.VizieR/J/AJ/147/42
- Title:
- V light curves of EP Cep, ES Cep, and V369 Cep
- Short Name:
- J/AJ/147/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 188 is a good laboratory for studying the formation and evolution of W UMa type contact binaries due to its rich populations of them. We present a detailed photometric study of three short-period close binaries, EP Cep, ES Cep, and V369 Cep, in the old open cluster NGC 188 based on our two-set photometric observations. We discovered that both EP Cep and ES Cep are shallow-contact binaries with continuously decreasing periods. The difference is in their mass ratios. EP Cep has an extremely low-mass ratio, q=0.15, while ES Cep has a relatively high-mass ratio, q=0.69, indicating that they lie in different evolutionary stages. ES Cep is likely a newly formed contact binary via a Case A mass transfer, while EP Cep is an evolved system and may be on the oscillations caused by the combined effect of the thermal relaxation oscillation and the variable angular momentum loss. For another system, V369 Cep, we found that it is a primary-filling near-contact binary. Both the semidetached configuration and the continuous decrease in the orbital period indicate that it is undergoing a mass transfer from the primary component to the secondary one. This conclusion is in agreement with the excess luminosity seen in the light curves on the ingress of the secondary minimum produced by the impact of the mass transfer. All of the results suggest that V369 Cep is evolving into contact, and a shallow-contact high-mass ratio system similar to ES Cep will be formed. Then, it will evolve into a low-mass ratio contact binary just like EP Cep, and finally merge into a rapidly rotating single star.
