- ID:
- ivo://CDS.VizieR/J/ApJ/768/99
- Title:
- X-ray survey of YSOs in Orion A
- Short Name:
- J/ApJ/768/99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an XMM-Newton survey of the part of the Orion A cloud south of the Orion Nebula. This survey includes the Lynds 1641 (L1641) dark cloud, a region of the Orion A cloud with very few massive stars and hence a relatively low ambient UV flux, and the region around the O9III star {iota} Orionis. In addition to proprietary data, we used archival XMM data of the Orion Nebula Cluster (ONC) to extend our analysis to a major fraction of the Orion A cloud. We have detected 1060 X-ray sources in L1641 and the {iota} Ori region. About 94% of the sources have Two Micron All Sky Survey and Spitzer counterparts, 204 and 23 being Class II and Class I or protostar objects, respectively. In addition, we have identified 489 X-ray sources as counterparts to Class III candidates, given they are bright in X-rays and appear as normal photospheres at mid-IR wavelengths. The remaining 205 X-ray sources are likely distant active galactic nuclei or other galactic sources not related to Orion A. We find that Class III candidates appear more concentrated in two main clusters in L1641. The first cluster of Class III stars is found toward the northern part of L1641, concentrated around {iota} Ori. The stars in this cluster are more evolved than those in the Orion Nebula. We estimate a distance of 300-320 pc for this cluster showing that it is in the foreground of the Orion A cloud. Another cluster rich in Class III stars is located in L1641 South and appears to be a slightly older cluster embedded in the Orion A cloud. Furthermore, other evolved Class III stars are found north of the ONC toward NGC 1977.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/788/48
- Title:
- X-ray through NIR photometry of NGC 2617
- Short Name:
- J/ApJ/788/48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- After the All-Sky Automated Survey for SuperNovae discovered a significant brightening of the inner region of NGC 2617, we began a ~70 day photometric and spectroscopic monitoring campaign from the X-ray through near-infrared (NIR) wavelengths. We report that NGC 2617 went through a dramatic outburst, during which its X-ray flux increased by over an order of magnitude followed by an increase of its optical/ultraviolet (UV) continuum flux by almost an order of magnitude. NGC 2617, classified as a Seyfert 1.8 galaxy in 2003, is now a Seyfert 1 due to the appearance of broad optical emission lines and a continuum blue bump. Such "changing look active galactic nuclei (AGNs)" are rare and provide us with important insights about AGN physics. Based on the H{beta} line width and the radius-luminosity relation, we estimate the mass of central black hole (BH) to be (4+/-1)x10^7^ M_{sun}_. When we cross-correlate the light curves, we find that the disk emission lags the X-rays, with the lag becoming longer as we move from the UV (2-3 days) to the NIR (6-9 days). Also, the NIR is more heavily temporally smoothed than the UV. This can largely be explained by a simple model of a thermally emitting thin disk around a BH of the estimated mass that is illuminated by the observed, variable X-ray fluxes.
3633. XX Cep BVRI light curves
- ID:
- ivo://CDS.VizieR/J/MNRAS/379/1665
- Title:
- XX Cep BVRI light curves
- Short Name:
- J/MNRAS/379/1665
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We obtained CCD photometric observations of the Algol-type semidetached binary XX Cephei (XX Cep) during 15 nights from 2002 September 17 to 2003 February 2, and also on 2005 January 21. Except for those data taken on the last night of the concentrated observing season, the 3881 measurements were obtained over an interval of only 106 nights. From these data, four new times of minimum light were calculated. The (O-C) diagram formed from all available timings, and thus the orbital period of the system, can be partly represented as a beat effect between two cyclical variations with different periods (P1'=42yr, P2'=181yr) and amplitudes (K1=0.015d, K2=0.103d), respectively. Both physical and non-physical interpretations of these cycles were investigated.
3634. XXL Survey. DR2
- ID:
- ivo://CDS.VizieR/IX/52
- Title:
- XXL Survey. DR2
- Short Name:
- IX/52
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the second data release (DR2) of the XXL Survey, contextually with the appearance of a second A&A special issue dedicated to XXL. This intermediate release includes the following catalogues and data: The X-ray point source catalogue (3XLSS) and the associated multiwavelength catalogues in the XXL-N and XXL-s areas (XXL paper XXVII). The same paper also provides the list of XMM pointings used, and a supplementary catalogue of redshifts obtained with the AAOmega spectrograph in the XXL-S area. The XXL-365-GC galaxy cluster catalogue (XXL paper XX) with the complete subset of clusters for which the selection function is well determined plus all X-ray clusters which are, to date, spectroscopically confirmed. The ATCA 2.1 GHz radio source catalogue in the XXL-S area (XXL paper XXVIII), together with the catalogue of ther optical and near infrared counterparts (XXL paper XXVI). The GMRT 610 MHz radio source catalogue in the XXL-N area (XXL paper XXIX). FITS images of the XXL-North field: continuum radio mosaic from observations with the Giant Meterwave Radio Telescope (GMRT) at 610MHz, and the corresponding noise map. A complete spectrophotometric sample of galaxies within X-ray detected, optically spectroscopically confirmed groups and clusters (G&C), including also field objects, in the XXL-N area (XXL paper XXII). The list of brightest cluster galaxies (BCGs) in the XXL-N area (XXL paper XXVIII). FITS images of the two radio galaxies described in XXL paper XXXIV. ATCA XXL-S source classification data (XXL paper XXXVI) http://sci.esa.int/xmm-newton/60686-tracing-the-universe-x-ray-survey-\ supports-standard-cosmological-model/ List of XXL DR2 papers: XVI. The clustering of X-ray selected galaxy clusters at z~0.3 XVII. X-ray and Sunyaev-Zel'dovich properties of the redshift 2.0 galaxy cluster XLSSC 122 XVIII. ATCA 2.1 GHz radio source catalogue and source counts for the XXL-South field XIX. A realistic population of simulated X-ray AGN: Comparison of models with observations XX. The 365 cluster catalogue XXI. The environment and clustering of X-ray AGN in the XXL-South field XXII. The XXL-North spectrophotometric sample and galaxy stellar mass function in X-ray detected groups and clusters XXIII. The mass scale of XXL clusters from ensemble spectroscopy XXIV. The final detection pipeline XXV. Cosmological analysis of the C1 cluster number counts XXVI. Optical and near infrared identification of the ATCA 2.1 GHz radio sources in the XXL-S field XXVII. The 3XLSS point source catalogue XXVIII. Galaxy luminosity functions of the XXL-N clusters XXIX. GMRT 610 MHz continuum observations XXX. Characterisation of the XLSSsC N01 supercluster and analysis of the galaxy stellar populations XXXI. Classification and host galaxy properties of 2.1 GHz ATCA XXL-S radio sources XXXII. Spatial clustering of the XXL-S AGN XXXIII. Chandra constraints on the AGN contamination of z > 1 XXL galaxy clusters XXXIV. Double irony in XXL-North. A tale of two radio galaxies in a supercluster at z = 0.14 XXXV. The role of cluster mass in AGN activity XXXVI. Evolution and black hole feedback of high-excitation and low-excitation radio galaxies in XXL-S
- ID:
- ivo://CDS.VizieR/J/MNRAS/427/1517
- Title:
- XY And and UZ Vir light curves
- Short Name:
- J/MNRAS/427/1517
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a thorough analysis of multicolour CCD observations of two modulated RRab-type variables, XY And and UZ Vir. These Blazhko stars show relatively simple light-curve modulation with the usual multiplet structures in their Fourier spectra. One additional, independent frequency with linear-combination terms of the pulsation frequency is also detected in the residual spectrum of each of the two stars. The amplitude and phase relations of the triplet components are studied in detail. Most of the epoch-independent phase differences show a slight, systematic colour dependence. However, these trends have opposite signs in the two stars. The mean values of the global physical parameters and their changes with the Blazhko phase are determined, utilizing the inverse photometric method (IPM). The modulation properties and the IPM results are compared for the two variables. The pulsation period of XY And is the shortest when its pulsation amplitude is the highest, while UZ Vir has the longest pulsation period at this phase of the modulation. Despite this contrasting behaviour, the phase relations of the variations in their mean physical parameters are similar. These results do not agree with the predictions of the Blazhko model of Stothers.
3636. XY UMa BVRI light curves
- ID:
- ivo://CDS.VizieR/J/AJ/139/1801
- Title:
- XY UMa BVRI light curves
- Short Name:
- J/AJ/139/1801
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New CCD photometric observations of the chromospherically active binary XY Ursae Majoris (XY UMa) were obtained every year since 2006. The light curves obtained in the late Spring of 2006 show obvious variations on a short timescale, while the light curves obtained in 2008 December do not. But both sets of light curves are markedly asymmetric, and were analyzed using the 2003 version of the Wilson-Devinney code with spot model. New absolute physical parameters are obtained.
- ID:
- ivo://CDS.VizieR/J/A+A/563/A120
- Title:
- Y Cyg light curves and time of minima
- Short Name:
- J/A+A/563/A120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Rapid advancements in light-curve and radial-velocity curve modelling, as well as improvements in the accuracy of observations, allow more stringent tests of the theory of stellar evolution. Binaries with rapid apsidal advance are particularly useful in this respect since the internal structure of the stars can also be tested. Thanks to its long and rich observational history and rapid apsidal motion, the massive eclipsing binary Y Cyg represents one of the cornerstones of critical tests of stellar evolutionary theory for massive stars. Nevertheless, the determination of the basic physical properties is less accurate than it could be given the existing number of spectral and photometric observations. Our goal is to analyse all these data simultaneously with the new dedicated series of our own spectral and photometric observations from observatories widely separated in longitude.
- ID:
- ivo://CDS.VizieR/J/ApJS/190/203
- Title:
- 3.6 years of DIRBE NIR stellar light curves
- Short Name:
- J/ApJS/190/203
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The weekly averaged near-infrared fluxes for 2652 stars were extracted from the cold and warm era all-sky maps of the Diffuse Infrared Background Experiment (DIRBE). Since the DIRBE program only archived the individual Calibrated Infrared Observations for the 10 month cold era mission, the weekly averaged fluxes were all that were available for the warm era. The steps required to extract stellar fluxes are described as are the adjustments that were necessary to correct the results for several systematic effects. The observations are at a cadence of once a week for 3.6 years (~1300 days), providing continuous sampling on variable stars that span the entire period for the longest fundamental pulsators. The stars are divided into three categories: those with large amplitude of variability, smaller amplitude variables, and sources whose near-infrared brightness do not vary according to our classification criteria. We show examples of the results and the value of the added baseline in determining the phase lag between the visible and infrared.
- ID:
- ivo://CDS.VizieR/J/MNRAS/434/38
- Title:
- 25-years photometry of V1057 Cygni
- Short Name:
- J/MNRAS/434/38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The FU Orionis type of variable star (FUor), V1057 Cygni, underwent a nova-like outburst in 1969-1970. Among the FUors, V1057 Cyg is notable for having the most dramatic post-maximum decrease in brightness. Thus, photometric monitoring of this object is important for interpretations of the cause of this event. Here, we study the behaviour of V1057 Cyg over the last 25 years on the basis of our optical and infrared observations. The optical and near-infrared observations of V1057 Cyg started in 1974, and we present all our data (up to the end of 2011), including 1085 and 167 nights of optical and infrared photometry, respectively. The UBVRIJHKLM light curves for 1985-2011 show that despite the increased photometric activity, after a rapid decrease in brightness in the mid-1990s, the average level of brightness remained practically constant. After the object becomes fainter than V~11.5mag, a swerve appears in the track of the colour-magnitude diagram. The light variability shows a different periodicity in different spectral regions. We have discovered a period of 1631+/-60d in the BVR bands (1995-2011) and 523+/-40d in the RIJHK bands (2002-2011) with amplitudes of 0.5-0.3mag. The 523-d period is presumably correlated with the changes in the radial velocity of an emission component in LiI. We conclude that the observed properties of the FUor star V1057 Cyg are in accordance with current models of FUors involving binary or multiple systems.
- ID:
- ivo://CDS.VizieR/J/AJ/159/266
- Title:
- 12 years positional measurements of 8 binaries
- Short Name:
- J/AJ/159/266
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The orbits of eight systems with low-mass components (HIP14524, HIP16025, HIP28671, HIP46199, HIP47791, HIP60444, HIP61100, and HIP73085) are presented. Speckle interferometric data were obtained at the 6m Big Telescope Alt-azimuth Special Astrophysical Observatory of the Russian Academy of Sciences (BTA SAO RAS) from 2007 to 2019. New data, together with measures already in the literature, made it possible to improve upon previous orbital solutions in six cases and to construct orbits for the first time in the two remaining cases (HIP14524 and HIP60444). Mass sums are obtained using both Hipparcos and Gaia parallaxes, and a comparison with previously published values is made. Using the Worley & Heintz criteria, the classification of the orbits constructed is carried out.
