- ID:
- ivo://CDS.VizieR/J/ApJ/876/8
- Title:
- BVI LCs and radial velocities of PSR J1306-40
- Short Name:
- J/ApJ/876/8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- PSR J1306-40 is a millisecond pulsar (MSP) binary with a non-degenerate companion in an unusually long ~1.097 day orbit. We present new optical photometry and spectroscopy of this system, and model these data to constrain fundamental properties of the binary such as the component masses and distance. The optical data imply a minimum neutron star mass of 1.75+/-0.09M_{sun}_ (1{sigma}) and a high, nearly edge-on inclination. The light curves suggest a large hot spot on the companion, suggestive of a portion of the pulsar wind being channeled to the stellar surface by the magnetic field of the secondary, mediated via an intrabinary shock. The H{alpha} line profiles switch rapidly from emission to absorption near the companion inferior conjunction, consistent with an eclipse of the compact emission region at these phases. At our optically inferred distance of 4.7+/-0.5kpc, the X-ray luminosity is ~10^33^erg/s, brighter than nearly all known redbacks in the pulsar state. The long-period, subgiant-like secondary, and luminous X-ray emission suggest this system may be part of the expanding class of MSP binaries that are progenitors to typical field pulsar-white dwarf binaries.
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- ID:
- ivo://CDS.VizieR/J/A+A/416/1037
- Title:
- BVRIK Photometry for the field of 4U 0142+61
- Short Name:
- J/A+A/416/1037
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new optical and infrared observations of the counterpart to the Anomalous X-ray Pulsar (AXP) 4U 0142+61 taken with the Keck I telescope. The counterpart is found to be variable in the infrared. This contrasts with our optical observations, which do not show any evidence for variability. Apart from the variability the AXP shows a remarkable spectral energy distribution. In particular, we find a sudden drop in flux going from V to B, presumably due to a spectral feature. We compare our results to those obtained for the two other securely identified AXP counterparts, to 1E 2259+586 and 1E 1048.1-5937. 4U 0142+61 is very similar to the former source in its X-ray timing and spectral properties, and we find that this similarity extends to the quiescent infrared to X-ray flux ratio. For 1E 1048.1-5937, which has different X-ray properties, the situation is less clear: in one observation, the infrared to X-ray flux ratio was much larger, but another observation gave an upper limit which is consistent with that observed for 4U 0142+61. Assuming the quiescent ratios are all similar, we estimate the optical and infrared brightnesses for the three AXPs that remain to be identified as well as for the four Soft Gamma-ray Repeaters. We also discuss briefly how the observed optical and infrared emission might arise, in particular in the context of the magnetar model.
- ID:
- ivo://CDS.VizieR/VII/189
- Title:
- Catalog of Pulsars
- Short Name:
- VII/189
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalogue is a compilation of the principal observed parameters of 706 pulsars (updated from 558 pulsars in the previous version), including positions, timing parameters, pulse widths, flux densities, proper motions, distances, and dispersion, rotation, and scattering measures. It also lists the orbital elements of binary pulsars, and some commonly used parameters derived from the basic measurements. Uncertainties are quoted for most quantities.
- ID:
- ivo://CDS.VizieR/VII/156
- Title:
- Catalog of 558 Pulsars
- Short Name:
- VII/156
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalogue is an up-to-date compilation of the principal observed parameters of 558 pulsars, including positions, timing parameters, pulse widths, flux densities, proper motions, distances, and dispersion, rotation, and scattering measures. It also lists the orbital elements of binary pulsars, and some commonly used parameters derived from the basic measurements. Uncertainties are quoted for most quantities.
- ID:
- ivo://CDS.VizieR/J/ApJ/716/1217
- Title:
- Chandra SMC deep field sources
- Short Name:
- J/ApJ/716/1217
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a pair of 100ks Chandra observations in the Small Magellanic Cloud (SMC) to survey high-mass X-ray binaries (HMXBs), stars, and low-mass X-ray binaries (LMXBs)/cataclysmic variables down to L_x_=4.3x10^32^erg/s. The two SMC Deep Fields (DFs) are located in the most active star-forming region of the bar, with Deep Field-1 positioned at the most pulsar-rich location identified from previous surveys. Two new pulsars were discovered in the outburst: CXOU J004929.7-731058 (P=892s), CXOU J005252.2-721715 (P=326s), and three new HMXB candidates were identified. Of the 15 Be-pulsars now known in the field, 13 were detected, with pulsations seen in 9 of them. Bright optical counterparts exist for 40 of the X-ray sources, of which 33 are consistent with early-type stars (M_V_<-2, B-V<0.2), and are the subject of a companion paper. The results point to an underlying HMXB population density up to double that of active systems. The full catalog of 394 point sources is presented along with detailed analyses of timing and spectral properties.
- ID:
- ivo://CDS.VizieR/J/ApJ/709/241
- Title:
- Characterisation of X-rays sources in NGC 6397
- Short Name:
- J/ApJ/709/241
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a deep Chandra X-ray Observatory study of the peculiar binary radio millisecond pulsar (MSP) PSR J1740-5340 and candidate millisecond pulsars in the globular cluster NGC 6397. The X-rays from PSR J1740-5340 appear to be non-thermal and exhibit variability at the binary period. These properties suggest the presence of a relativistic intrabinary shock formed due to interaction of a relativistic rotation-powered pulsar wind and outflow from the unusual "red-straggler/sub-subgiant" companion. We find the X-ray source U18 to show similar X-ray and optical properties to those of PSR J1740-5340, making it a strong MSP candidate. It exhibits variability on timescales from hours to years, also consistent with an intrabinary shock origin of its X-ray emission. The unprecedented depth of the X-ray data allows us to conduct a complete census of MSPs in NGC 6397. Based on the properties of the present sample of X-ray-detected MSPs in the Galaxy, we find that NGC 6397 probably hosts no more than six MSPs.
- ID:
- ivo://CDS.VizieR/J/MNRAS/391/1210
- Title:
- Characteristics of energetic pulsars
- Short Name:
- J/MNRAS/391/1210
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we compare the characteristics of pulsars with a high spin-down energy loss rate (Edot) against those with a low Edot. We show that the differences in the total intensity pulse morphology between the two classes are in general rather subtle. A much more significant difference is the fractional polarization which is very high for high Edot pulsars and low for low Edot pulsars. The Edot at the transition is very similar to the death line predicted for curvature radiation. This suggests a possible link between high energy and radio emission in pulsars and could imply that gamma-ray efficiency is correlated with the degree of linear polarization in the radio band. As part of this study, we have discovered three previous unknown interpulse pulsars (and we detected one for the first time at 20cm). We also obtained rotation measures for 18 pulsars whose values had not previously been measured.
- ID:
- ivo://CDS.VizieR/J/ApJS/255/5
- Title:
- CHIME/Pulsar 400-800MHz obs. of ATNF pulsars
- Short Name:
- J/ApJS/255/5
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present the design, implementation, and performance of the digital pulsar observing system constructed for the Canadian Hydrogen Intensity Mapping Experiment (CHIME). Using accelerated computing, this system processes independent, digitally steered beams formed by the CHIME correlator to simultaneously observe up to 10 radio pulsars and transient sources. Each of these independent streams is processed by the CHIME/Pulsar back-end system, which can coherently dedisperse, in real time, up to dispersion measure values of 2500pc/cm^3^. The tracking beams and real-time analysis system are autonomously controlled by a priority-based algorithm that schedules both known sources and positions of interest for observation with observing cadences as rapid as 1 day. Given the distribution of known pulsars and radio-transient sources and the dynamic scheduling, the CHIME/Pulsar system can monitor 400-500 positions once per sidereal day and observe most sources with declinations greater than -20{deg} once every ~4 weeks. We also discuss the extensive science program enabled through the current modes of data acquisition for CHIME/Pulsar that centers on timing and searching experiments.
- ID:
- ivo://CDS.VizieR/J/other/ChJAA/6.237
- Title:
- Circular polarization in pulsars
- Short Name:
- J/other/ChJAA/6.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We update the systematic studies of circular polarization in integrated pulse profiles by Han et al. (1998MNRAS.300..373H). Data of circular polarization profiles are compiled. Sense reversals can occur in core or cone components, or near the intersection between components. The correlation between the sense of circular polarization and the sense of position angle variation for conal-double pulsars is confirmed with a much large database. Circular polarization of some pulsars has clear changes with frequency. Circular polarization of millisecond pulsars is marginally different from that of normal pulsars.
- ID:
- ivo://CDS.VizieR/J/ApJ/887/18
- Title:
- Classification of X-ray counterparts of 3FGL sources
- Short Name:
- J/ApJ/887/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Approximately one-third of the gamma-ray sources in the third Fermi-LAT catalog are unidentified or unassociated with objects at other wavelengths. Observations with the X-Ray Telescope on the Neil Gehrels Swift Observatory (Swift-XRT) have yielded possible counterparts in ~30% of these source regions. The objective of this work is to identify the nature of these possible counterparts, utilizing their gamma-ray properties coupled with the Swift derived X-ray properties. The majority of the known sources in the Fermi catalogs are blazars, which constitute the bulk of the extragalactic gamma-ray source population. The galactic population on the other hand is dominated by pulsars. Overall, these two categories constitute the majority of all gamma-ray objects. Blazars and pulsars occupy different parameter space when X-ray fluxes are compared with various gamma-ray properties. In this work, we utilize the X-ray observations performed with the Swift-XRT for the unknown Fermi sources and compare their X-ray and gamma-ray properties to differentiate between the two source classes. We employ two machine-learning algorithms, decision tree and random forest (RF) classifier, to our high signal-to-noise ratio sample of 217 sources, each of which corresponds to Fermi unassociated regions. The accuracy scores for both methods were found to be 97% and 99%, respectively. The RF classifier, which is based on the application of a multitude of decision trees, associated a probability value (P_bzr_) for each source to be a blazar. This yielded 173 blazar candidates from this source sample, with P_bzr_>=90% for each of these sources, and 134 of these possible blazar source associations had P_bzr_>=99%. The results yielded 13 sources with P_bzr_<=10%, which we deemed as reasonable candidates for pulsars, seven of which result with P_bzr_<=1%. There were 31 sources that exhibited intermediate probabilities and were termed ambiguous due to their unclear characterization as a pulsar or a blazar.
