- ID:
- ivo://CDS.VizieR/J/ApJ/872/56
- Title:
- R-band linear polarization of Gaia stars
- Short Name:
- J/ApJ/872/56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The availability of large data sets with stellar distance and polarization information will enable a tomographic reconstruction of the (plane-of-the-sky-projected) interstellar magnetic field in the near future. We demonstrate the feasibility of such a decomposition within a small region of the diffuse interstellar medium (ISM). We combine measurements of starlight (R-band) linear polarization obtained using the RoboPol polarimeter with stellar distances from the second Gaia data release. The stellar sample is brighter than 17mag in the R-band and reaches out to several kiloparsecs from the Sun. HI emission spectra reveal the existence of two distinct clouds along the line of sight. We decompose the line-of-sight-integrated stellar polarizations to obtain the mean polarization properties of the two clouds. The two clouds exhibit significant differences in terms of column density and polarization properties. Their mean plane-of-the-sky magnetic field orientation differs by 60{deg}. We show how our tomographic decomposition can be used to constrain our estimates of the polarizing efficiency of the clouds as well as the frequency dependence of the polarization angle of polarized dust emission. We also demonstrate a new method to constrain cloud distances based on this decomposition. Our results represent a preview of the wealth of information that can be obtained from a tomographic map of the ISM magnetic field.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/747/L5
- Title:
- R-band observations of PTF 10vgv
- Short Name:
- J/ApJ/747/L5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discovery of PTF 10vgv, a Type Ic supernova (SN) detected by the Palomar Transient Factory, using the Palomar 48 inch telescope (P48). R-band observations of the PTF 10vgv field with P48 probe the SN emission from its very early phases (about two weeks before R-band maximum) and set limits on its flux in the week prior to the discovery. Our sensitive upper limits and early detections constrain the post-shock-breakout luminosity of this event. Via comparison to numerical (analytical) models, we derive an upper-limit of R<~4.5R_{sun}_ (R<~1R_{sun}_) on the radius of the progenitor star, a direct indication in favor of a compact Wolf-Rayet star. Applying a similar analysis to the historical observations of SN 1994I yields R<~1/4R_{sun}_ for the progenitor radius of this SN.
- ID:
- ivo://CDS.VizieR/J/AJ/157/186
- Title:
- r'-band photometry of comet 96P/Machholz 1
- Short Name:
- J/AJ/157/186
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed comet 96P/Machholz 1 on a total of nine nights before and after perihelion during its 2017/2018 apparition. Both its unusually small perihelion distance and the observed fragmentation during multiple apparitions make 96P an object of great interest. Our observations show no evidence of a detectable dust coma, implying that we are observing a bare nucleus at distances ranging from 2.3 to 3.8 au. Based on this assumption, we calculated its color and found average values of g'-r'=0.50+/-0.04, r'-i'=0.17+/-0.03, and i'-z'=0.06+/-0.04. These are notably more blue than those of the nuclei of other Jupiter-family and long-period comets. Furthermore, assuming a bare nucleus, we found an equivalent nuclear radius of 3.4+/-0.2 km with an axial ratio of at least 1.6+/-0.1. The lightcurve clearly displays one large peak, one broad flat peak, and two distinct troughs, with a clear asymmetry that suggests that the shape of the nucleus deviates from that of a simple triaxial ellipsoid. This asymmetry in the lightcurve allowed us to constrain the nuclear rotation period to 4.10+/-0.03 hr and 4.096+/-0.002 hr before and after perihelion, respectively. Within the uncertainties, 96P's rotation period does not appear to have changed throughout the apparition, and we conclude a maximum possible change in rotation period of 130 s. The observed properties were compared to those of comet 322P and interstellar object 1I/'Oumuamua in an attempt to study the effects of close perihelion passages on cometary surfaces and their internal structure and the potential interstellar origin of 96P.
- ID:
- ivo://CDS.VizieR/J/ApJ/811/117
- Title:
- R-band PTF observations of SNe IIb
- Short Name:
- J/ApJ/811/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The progenitor stars of several Type IIb supernovae (SNe) show indications of extended hydrogen envelopes. These envelopes might be the outcome of luminous energetic pre-explosion events, so-called precursor eruptions. We use the Palomar Transient Factory (PTF) pre-explosion observations of a sample of 27 nearby SNe IIb to look for such precursors during the final years prior to the SN explosion. No precursors are found when combining the observations in 15-day bins, and we calculate the absolute-magnitude-dependent upper limit on the precursor rate. At the 90% confidence level, SNe IIb have on average <0.86 precursors as bright as an absolute R-band magnitude of -14 in the final 3.5 years before the explosion and <0.56 events over the final year. In contrast, precursors among SNe IIn have a >~5 times higher rate. The kinetic energy required to unbind a low-mass stellar envelope is comparable to the radiated energy of a few-weeks-long precursor that would be detectable for the closest SNe in our sample. Therefore, mass ejections, if they are common in such SNe, are radiatively inefficient or have durations longer than months. Indeed, when using 60-day bins, a faint precursor candidate is detected prior to SN 2012cs (~2% false-alarm probability). We also report the detection of the progenitor of SN 2011dh that does not show detectable variability over the final two years before the explosion. The suggested progenitor of SN 2012P is still present, and hence is likely a compact star cluster or an unrelated object.
- ID:
- ivo://CDS.VizieR/J/ApJ/731/118
- Title:
- R-band variability in blazar S5 0716+71
- Short Name:
- J/ApJ/731/118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report rapid optical variability for the blazar S5 0716+71 during 2010 March 8-10 and 19-20 in the CCD observations made from Mt. Abu Infrared Observatory. The light curves are constructed for a duration longer than 3hr each night, with very high temporal resolution (~45s in the R band). During 2010 March 8, the source smoothly decayed by about 0.15mag in 2.88hr, apart from a fast flicker lasting about 30 minutes. S5 0716+71 brightened during March 9 and 10, showing high activity, while it was relatively faint (>14mag in the R band) albeit variable during March 19-20. During March 9 and 10, rapid flickers in the intensity modulated the long-term intra-night (~3hr) variations. The present observations suggest that the blazar S5 0716+71 showed night-to-night and intra-night variability at various timescales with a 100% duty cycle for variation along with microvariability at significant levels. On a night-to-night basis, the source exhibits mild bluer-when-brighter nature. The interaction of shocks with local inhomogeneities in the jet appears to cause intra-night variations, while microvariations could be due to small-scale perturbations intrinsic to the jet.
- ID:
- ivo://CDS.VizieR/J/ApJ/837/45
- Title:
- 2006-2012 Rc-band & 4.8GHz obs. of AO 0235+164
- Short Name:
- J/ApJ/837/45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Variability is one of the extreme observational properties of BL Lacertae objects. AO 0235+164 is a well-studied BL Lac throughout all electromagnetic wavebands. In the present work, we show its optical R-band photometric observations carried out during the period from 2006 November to 2012 December using the Ap6E CCD camera attached to the primary focus of the 70cm meniscus telescope at Abastumani Observatory, Georgia. During our monitoring period, it showed a large variation of {Delta}R=4.88mag (14.19-19.07mag) and a short timescale of {Delta}T_v_=73.5minutes. During the period of 2006 December to 2009 November, we made radio observations of the source using the 25m radio telescope at Xinjiang Astronomical Observatory. By adopting a discrete correlation function to the optical and radio observations we found that the optical variation leads a radio variation of 23.2+/-12.9days.
- ID:
- ivo://CDS.VizieR/J/MNRAS/351/1401
- Title:
- RcIcZ photometry of NGC 2547
- Short Name:
- J/MNRAS/351/1401
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of RcIcZ photometry over an area of 0.855 square degrees, centred on the young open cluster NGC 2547. The survey is substantially complete to limits of Rc=21.5, Ic=19.5, Z=19.5. We use the catalogue to define a sample of NGC 2547 candidates with model-dependent masses of about 0.05-1.0M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/A+A/376/561
- Title:
- Rc light curves of 7 variables in M37
- Short Name:
- J/A+A/376/561
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A CCD photometric study of the dense galactic open cluster M 37 is discussed. The majority of the analysed data have been obtained through an R_C_ filter in order to collect time-series measurements. The observations were carried out on seven nights between December 1999 and February 2000, and have led to the discovery of 7 new variable stars in the field. Three of them have been unambiguously identified as W UMa-type eclipsing binaries, while two more are monoperiodic pulsating stars, most probably high-amplitude {delta} Scuti-type variables. Two stars seem to be long-period eclipsing binaries without firm period determination. The individual light curve data are presented here.
- ID:
- ivo://CDS.VizieR/J/AN/333/242
- Title:
- Recent photometry of symbiotic stars
- Short Name:
- J/AN/333/242
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new multicolour (U,B,V,Rc,Ic) photometric observations of classical symbiotic stars, EG And, Z And, BF Cyg, CH Cyg, CI Cyg, V1329 Cyg, TX CVn, AG Dra, Draco C1, AG Peg and AX Per, carried out between 2007.1 and 2011.9. The aim of this paper is to present new data of our monitoring programme, to describe the main features of their light curves (LC) and to point problems for their future investigation. The data were obtained by the method of the classical photoelectric and CCD photometry.
- ID:
- ivo://CDS.VizieR/J/MNRAS/418/2054
- Title:
- Recession velocities for fossil galaxy groups
- Short Name:
- J/MNRAS/418/2054
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Defined as X-ray bright galaxy groups with large differences between the luminosities of their brightest and second brightest galaxies, "fossil groups" are believed to be some of the oldest galaxy systems in the Universe. They have therefore been the subject of much recent research. In this work we present a study of 10 fossil group candidates with an average of 33 spectroscopically confirmed members per group, making this the deepest study of its type to date. We also use these data to perform an analysis of the luminosity function of our sample of fossil groups.
