<i>CHANDRA</i>X-RAY OBSERVATIONS OF THE TWO BRIGHTEST UNIDENTIFIED HIGH GALACTIC LATITUDE<i>FERMI</i>-LAT γ-RAY SOURCES

Cheung, C. C.; Donato, D.; Gehrels, N.; Sokolovsky, K. V.; Giroletti, M.

doi:10.1088/0004-637x/756/1/33

Cited by 30 publications

(39 citation statements)

References 49 publications

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“…∼1-10 keV band(e.g., Saz . It is beyond the scope of this paper to carry out an exhaustive analysis of all the X-ray observations of LAT sources, many of which have, in any case, been published and discussed elsewhere(e.g., Cheung et al 2012). Here, we briefly discuss six interesting LAT sources for which we (PI: Saz Parkinson) obtained either Chandra or XMM observations.…”

Section: X-ray Observationsmentioning

confidence: 99%

Classification and Ranking of Fermi Lat Gamma-Ray Sources From the 3fgl Catalog Using Machine Learning Techniques

Parkinson

et al. 2016

ApJ

135

174

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We apply a number of statistical and machine learning techniques to classify and rank gamma-ray sources from the Third Fermi Large Area Telescope Source Catalog (3FGL), according to their likelihood of falling into the two major classes of gamma-ray emitters: pulsars (PSR) or active galactic nuclei (AGNs). Using 1904 3FGL sources that have been identified/associated with AGNs (1738) and PSR (166), we train (using 70% of our sample) and test (using 30%) our algorithms and find that the best overall accuracy (>96%) is obtained with the Random Forest (RF) technique, while using a logistic regression (LR) algorithm results in only marginally lower accuracy. We apply the same techniques on a subsample of 142 known gamma-ray pulsars to classify them into two major subcategories: young (YNG) and millisecond pulsars (MSP). Once more, the RF algorithm has the best overall accuracy (∼90%), while a boosted LR analysis comes a close second. We apply our two best models (RF and LR) to the entire 3FGL catalog, providing predictions on the likely nature of unassociated sources, including the likely type of pulsar (YNG or MSP). We also use our predictions to shed light on the possible nature of some gamma-ray sources with known associations (e.g., binaries, supernova remnants/pulsar wind nebulae). Finally, we provide a list of plausible X-ray counterparts for some pulsar candidates, obtained using Swift, Chandra, and XMM. The results of our study will be of interest both for in-depth follow-up searches (e.g., pulsar) at various wavelengths and for broader population studies.

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Section: X-ray Observationsmentioning

confidence: 99%

Classification and Ranking of Fermi Lat Gamma-Ray Sources From the 3fgl Catalog Using Machine Learning Techniques

Parkinson

et al. 2016

ApJ

135

174

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“…Our counterpart, source 38 in the 21 ks Chandra X-ray Observatory ACIS observation of Cheung et al (2012), provides ∼350 X-ray photons. We fit these data to a power-law model with CIAO/SHERPA, finding a photon index Γ = 1.…”

Section: Archival X-ray Datamentioning

confidence: 99%

“…Our strategy (as used to identify J1311 and J2339) was to obtain initial 300 s g r i frames for near-simultaneous colors (August 10), followed by single-color photometric sequences: 15 × 300 s in g (August 10), 29 × 180 s in r (August 11), and 32 × 300 s in i (August 12). We were particularly interested in the eight Chandra X-ray sources in the revised error ellipse (see Cheung et al 2012). Four of these had optical counterparts in our frames.…”

Section: Photometry and Orbital-period Estimatementioning

confidence: 99%

2fgl J1653.6–0159: A New Low in Evaporating Pulsar Binary Periods

Romani

Filippenko

Cenko

2014

ApJ

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We have identified an optical binary with orbital period P b = 4488 s as the probable counterpart of the Fermi source 2FGL J1653.6−0159. Although pulsations have not yet been detected, the source properties are consistent with an evaporating millisecond pulsar binary; this P b = 75 minutes is the record low for a spin-powered system. The heated side of the companion shows coherent radial-velocity variations, with amplitude K = 666.9 ± 7.5 km s for a large mass function of f (M) = 1.60 ± 0.05 M . This heating suggests a pulsar luminosity ∼3 × 10 34 erg s −1 . The colors and spectra show an additional blue component dominating at binary minimum. Its origin is, at present, unclear. This system is similar to PSR J1311−3430, with a low-mass H-depleted companion, a dense shrouding wind and, likely, a large pulsar mass.

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“…In the 33.4 ks Suzaku observation, the pulsar showed unexpected flaring activity and some orbital modulation (Maeda et al 2011, Kataoka et al 2012). In the Chandra observation, the source's average position was in the chip gap, which significantly reduced the effective exposure (Cheung et al 2012). Prior to the source identification, we had proposed a short 10 ks observation of 2FGL J1311.7-3429 with Chandra to characterize its timing and spectral properties.…”

Section: Introductionmentioning

confidence: 99%

X-Ray Emission From J1446–4701, J1311–3430, and Other Black Widow Pulsars

Arumugasamy

Pavlov

Garmire

2015

ApJ

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We present the results of detailed X-ray analysis of two black-widow pulsars (BWPs), J1446-4701 and J1311-3430. PSR J1446-4701 is a BWP with orbital parameters near the median values of the sample of known BWPs. Its X-ray emission detected by XMM-Newton is well characterized by a soft power-law (PL) spectrum (photon index Γ ≈ 3), and it shows no significant orbital modulations. In view of a lack of radio eclipses and an optical non-detection, the system most likely has a low orbital inclination. PSR J1311-3430 is an extreme BWP with a very compact orbit and the lowest minimum mass companion. Our Chandra data confirm the hard, Γ ≈ 1.3, emission seen in previous observations. Through phase-restricted spectral analysis, we found a hint (∼ 2.6σ) of spectral hardening around pulsar inferior conjunction. We also provide a uniform analysis of the 12 BWPs observed with Chandra and compare their X-ray properties. Pulsars with soft, Γ > 2.5, emission seem to have lower than average X-ray and γ-ray luminosities. We do not, however, see any other prominent correlation between the pulsar's X-ray emission characteristics and any of its other properties. The contribution of the intra-binary shock to the total X-ray emission, if any, is not discernible in this sample of pulsars with shallow observations.

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CHANDRAX-RAY OBSERVATIONS OF THE TWO BRIGHTEST UNIDENTIFIED HIGH GALACTIC LATITUDEFERMI-LAT γ-RAY SOURCES

Cited by 30 publications

References 49 publications

Classification and Ranking of Fermi Lat Gamma-Ray Sources From the 3fgl Catalog Using Machine Learning Techniques

Classification and Ranking of Fermi Lat Gamma-Ray Sources From the 3fgl Catalog Using Machine Learning Techniques

2fgl J1653.6–0159: A New Low in Evaporating Pulsar Binary Periods

X-Ray Emission From J1446–4701, J1311–3430, and Other Black Widow Pulsars

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