One of the main results of the Fermi Gamma-Ray Space Telescope is the discovery of γ-ray selected pulsars. The high magnetic field pulsar, PSR J0007+7303 in CTA1, was the first ever to be discovered through its γ-ray pulsations. Based on analysis of 2 years of LAT survey data, we report on the discovery of γ-ray emission in the off-pulse phase interval at the ~ 6σ level. The flux from this emission in the energy range E \geq 100 MeV is F_100 = (1.73\pm0.40)\times10^(-8) photons/cm^2/s and is best fitted by a power law with a photon index of Γ = 2.54\pm0.14. The pulsed γ-ray flux in the same energy range is F_100 = (3.95\pm0.07)\times10^(-7) photons/cm^2/s and is best fitted by an exponentially-cutoff power-law spectrum with a photon index of Γ = 1.41 \pm 0.23 and a cutoff energy E_c = 4.04 \pm 0.20 GeV. We find no flux variability neither at the 2009 May glitch nor in the long term behavior. We model the γ-ray light curve with two high-altitude emission models, the outer gap and slot gap, and find that the model that best fits the data depends strongly on the assumed origin of the off-pulse emission. Both models favor a large angle between the magnetic axis and observer line of sight, consistent with the nondetection of radio emission being a geometrical effect. Finally we discuss how the LAT results bear on the understanding of the cooling of this neutron star.
We discuss the criteria to associate PSRs with SNRs, and summary 78 pairs of possible PSR-SNR associations which is the most complete sample so far. We refine them into three categories according to degree of reliability. Statistic study on PSR-SNR associations helps us understand massive star evolution and constrain pulsar's theory models.
There have been substantial improvements on Fermi Large Area Telescope (LAT) data and analysis tools since the last analysis on the mid-aged supernova remnant (SNR) Kes 79 (Auchettl et al. 2014). Recent multi-wavelength studies confirmed its interaction with molecular clouds. About $0.36\degr$ north from Kes 79, a powerful pulsar -- PSR J1853+0056 also deserves our attention. In this work, we analyse the 11.5-year Fermi-LAT data to investigate the $γ$-ray feature in/around this complex region. Our result shows a more significant detection ($\sim$34.8$σ$ in 0.1--50 GeV) for this region. With $\…
We have obtained a deep 670 ks CXO ACIS image of the remarkable pulsar wind nebula (PWN) of PSR J1709-4429, in 4 epochs during 2018-2019. Comparison with an archival 2004 data set provides a pulsar proper motion mu = 13 \pm 3 mas/yr at a PA of 86 \pm 9 degree (1 sigma combined statistical and systematic uncertainties), precluding birth near the center of SNR G343.1-2.3. At the pulsar's characteristic age of 17 kyr, the association can be preserved through a combination of progenitor wind, birth kick and PWN outflow. Associated TeV emission may, however, indicate explosion in an earlier superno…
We report on a new Chandra exposure of PSR J1809-2332, the recently discovered pulsar powering the bright EGRET source 3EG J1809-2328. By registration of field X-ray sources in an archival exposure, we measure a significant proper motion for the pulsar point source over an ~11 year baseline. The shift of 0.30+/-0.06" (at PA= 153.3+/-18.4) supports an association with proposed SNR parent G7.5-1.7. Spectral analysis of diffuse emission in the region also supports the interpretation as a hard wind nebula trail pointing back toward the SNR.
Context. The gamma-ray binary LS 5039 and the isolated pulsar PSR J1825-1446 were proposed to have been formed in the supernova remnant (SNR) G016.8-01.1. Aims. We aim to obtain the Galactic trajectory of LS 5039 and PSR J1825-1446 to find their origin in the Galaxy, and in particular to check their association with SNR G016.8-01.1 to restrict their age. Methods. By means of radio and optical observations we obtained the proper motion and the space velocity of the sources. Results. The proper motion of PSR J1825-1446 corresponds to a transverse space velocity of 690 km/s at a distance of 5 kpc…
The characteristic age of PSR J1734$-$3333 estimated from its current spin down rate implies that it is a young pulsar ($τ_c<10$ kyr). But the time derivative of its spin down rate differs markedly from that assumed for normal radio pulsars, meaning its actual age is uncertain. G354.8$-$0.8 is a supernova remnant (SNR) whose centre is located 21 arcmin away of the pulsar, and with a morphology that suggests an association with the pulsar. We want to assess the likelihood of the association between PSR J1734$-$3333 and G354.8$-$0.8 or other nearby supernova remnants quantitatively, with the obj…
We briefly reviewed some recent progress on the studies of supernova remnants (SNRs), including the radio SNRs (the structure, polarization, spectrum etc.), observational characteristics of X-ray emission, pulsar wind nebulae (PWNe), association properties between SNR and PSR, interaction of SNR and interstellar medium (ISM), cosmos ray and the SNRs in external galaxies, etc.. Correspondingly to the continue improvement of space and spectrum resolution of the on-ground and in-space astronomical equipments at wavelengthes as radio, optical, X-ray and so on, we know about SNRs more and deeper.
Energetic pulsars can be embedded in a nebula of relativistic leptons which is powered by the dissipation of the rotational energy of the pulsar. The object PSR J0855-4644 is an energetic and fast-spinning pulsar (Edot = 1.1x10^36 erg/s, P=65 ms) discovered near the South-East rim of the supernova remnant (SNR) RX J0852.0-4622 (aka Vela Jr) by the Parkes multibeam survey. The position of the pulsar is in spatial coincidence with an enhancement in X-rays and TeV gamma-rays, which could be due to its putative pulsar wind nebula (PWN). The purpose of this study is to search for diffuse non-therma…
The energetic pulsar PSR B1706-44 and the adjacent supernova remnant (SNR) candidate G 343.1-2.3 were observed by H.E.S.S. during a dedicated observational campaign in 2007. A new source of very-high-energy (VHE; E > 100 GeV) gamma-ray emission, HESS J1708-443, was discovered with its centroid at RA(J2000) = 17h08m10s and Dec(J2000) = -44d21', with a statistical error of 3 arcmin on each axis. The VHE gamma-ray source is significantly more extended than the H.E.S.S. point-spread function, with an intrinsic Gaussian width of 0.29 +/- 0.04 deg. Its energy spectrum can be described by a power law…
PSR B1706$-$44 is an energetic gamma-ray pulsar located inside supernova remnant (SNR) G343.1$-$2.3 and it powers a compact pulsar wind nebula (PWN) that shows torus and jet structure in X-rays. We present a radio study of the PWN using Australia Telescope Compact Array (ATCA) observations at 3, 6, 13, and 21\,cm. We found an overall arc-like morphology at 3 and 6\,cm, and the ``arc" shows two distinct peaks at 6\,cm. The radio emission is faint inside the X-ray PWN and only brightens beyond that. We develop a thick torus model with Doppler boosting effect to explain the radio PWN structure. T…
We report the ATCA and ROSAT detection of Supernova Remnant (SNR) J0529--6653 in the Large Magellanic Cloud (LMC) which is positioned in the projected vicinity of the known radio pulsar PSR B0529-66. In the radio-continuum frequencies, this LMC object follows a typical SNR structure of a shell morphology with brightened regions in the south-west. It exhibits an almost circular shape of D=33 x 31 pc (1 pc uncertainty in each direction) and radio spectral index of alpha=-0.68$+-$0.03 - typical for mid-age SNRs. We also report detection of polarised regions with a peak value of 17+-7% at 6 cm. An…
We report the discovery of PSR J2022+3842, a 24 ms radio and X-ray pulsar in the supernova remnant G76.9+1.0, in observations with the Chandra X-ray telescope, the Robert C. Byrd Green Bank Radio Telescope, and the Rossi X-ray Timing Explorer (RXTE). The pulsar's spin-down rate implies a rotation-powered luminosity Edot = 1.2 x 10^{38} erg/s, a surface dipole magnetic field strength B_s = 1.0 x 10^{12} G, and a characteristic age of 8.9 kyr. PSR J2022+3842 is thus the second-most energetic Galactic pulsar known, after the Crab, as well as the most rapidly-rotating young, radio-bright pulsar kn…
EMU discovery of Thunder: a bow-shock PWN powered by PSR J1631-4722 escaping Nimbus SNR (G336.7+0.5)
Western Sydney University（西悉尼大学）；Australia Telescope National Facility, CSIRO（澳大利亚望远镜国家设施，CSIRO）；Astronomical Observatory（天文台）；Inter University Centre for Astronomy & Astrophysics（大学间天文学与天体物理学中心）；Max-Planck-Institut für extraterrestrische Physik（马克斯·普朗克地外物理学研究所）；Faculty of Engineering, Gifu University（岐阜大学工学部）；Department of Physics and Astronomy, University of Calgary（卡尔加里大学物理与天文学系）；Department of Physics, The George Washington University（乔治华盛顿大学物理系）
HESS J1804-216 is one of the brightest yet most mysterious TeV gamma-ray sources discovered to date. Previous arc-minute scale studies of the interstellar medium (ISM) surrounding this TeV gamma-ray source revealed HESS J1804-216 is likely powered by a mature supernova remnant (SNR) or pulsar, hence its origin remains uncertain. In this paper, we focus on the diffusive escape of cosmic-ray protons from potential SNR accelerators. These cosmic rays interact with the ISM to produce TeV gamma-rays. We utilise the isotropic diffusion equation solution for particles escaping from a shell, to model …
In this work, we study theoretical and observational issues about pulsars (PSRs), pulsar wind nebulae (PWNe) and supernova remnants (SNRs). In particular, the spectral modeling of young PWNe and the X-ray analysis of SNRs with magnetars comparing their characteristics with those remnants surrounding canonical pulsars. The spectra of PWNe range from radio to $γ$-rays. They are the largest class of identified Galactic sources in $γ$-rays increasing the number from 1 to $\sim$30 during the last years. We have developed a detailed spectral code which reproduces the electromagnetic spectrum of PWNe…
We have investigated the field around the radio-quiet $γ$-ray pulsar, PSR J2021+4026, with a ~140 ks XMM-Newton observation and a ~56 ks archival Chandra data. Through analyzing the pulsed spectrum, we show that the X-ray pulsation is purely thermal in nature which suggests the pulsation is originated from a hot polar cap with $T\sim3\times10^{6}$ K on the surface of a rotating neutron star. On the other hand, the power-law component that dominates the pulsar emission in the hard band is originated from off-pulse phases, which possibly comes from a pulsar wind nebula. In re-analyzing the Chand…
We report the first rotation powered pulsars discovered in the Small Magellanic Cloud (SMC) in more than a decade. PSR J0043-73 and PSR J0052-72 were discovered during a Parkes Multi-Beam (PMB) survey of MCSNR J0127-7332, and five new, optically selected, supernova remnant (SNR) candidates identified by the XMM Newton survey. In addition to the candidates, we adjusted the PMB rotation to include an additional nine SNRs and pulsar wind nebulae. We searched for young pulsars (1 - 200 ms) employing a Fourier analysis with PRESTO, as well as a search for longer period pulsars (200 ms - 360 s) with…
We present broad-band X-ray spectroscopy of the energetic components that make up the supernova remnant (SNR) Kesteven 75 using concurrent 2017 Aug 17-20 XMM-Newton and NuSTAR observations, during which the pulsar PSR J1846-0258 is found to be in the quiescent state. The young remnant hosts a bright pulsar wind nebula powered by the highly-energetic (Edot = 8.1E36 erg/s) isolated, rotation-powered pulsar, with a spin-down age of only P/2Pdot ~ 728 yr. Its inferred magnetic field (Bs = 4.9E13 G) is the largest known for these objects, and is likely responsible for intervals of flare and burst a…
The composite supernova remnant (SNR) MSH 15-52 comprises the bright X-ray pulsar wind nebula (PWN) of PSR B1509-58, surrounded by a shell which is a prominent object in the radio domain. H.E.S.S. had discovered extended very-high-energy (VHE) gamma-ray emission coincident with the PWN. With additional H.E.S.S. observations performed since the 2005 discovery paper, we study the properties of the emission in greater detail. We compare the VHE gamma-ray morphology of the PWN with that in synchrotron emission, obtained from archival X-ray observations, and discuss the implications on the magnetic…
The Cygnus region is a nearby very active star forming region, containing several OB associations, considered as tracers of young pulsars. Above 12 TeV, the Milagro Collaboration has reported the discovery of a very large source, MGRO J2019+37, lying towards the Cyg OB1 association, at the edge of the Cygnus region. The young and energetic pulsar PSR J2021+3651 has been proposed to power this emission. We present here the result of deep VERITAS observations of this region at energies above 650 GeV. These observations unveil extended and complex TeV emission compatible with MGRO J2019+37, likel…
The Galactic TeV $γ$-ray source HESS$\,$J1804$-$216 is currently an unidentified source. In an attempt to unveil its origin, we present here the most detailed study of interstellar gas using data from the Mopra Southern Galactic Plane CO Survey, 7 and 12$\,$mm wavelength Mopra surveys and Southern Galactic Plane Survey of HI. Several components of atomic and molecular gas are found to overlap HESS$\,$J1804$-$216 at various velocities along the line of sight. The CS(1-0) emission clumps confirm the presence of dense gas. Both correlation and anti-correlation between the gas and TeV $γ$-ray emis…
We investigate the supernova remnant (SNR) 3C 397 and its neighboring pulsar PSR J1906+0722 in high energy gamma rays by using nearly six years of archival data of {\it Large Area Telescope} on board {\it Fermi Gamma Ray Space Telescope} (Fermi-LAT). The off-pulse analysis of gamma-ray flux from the location of PSR J1906+0722 reveals an excess emission which is found to be very close to the radio location of 3C 397. Here, we present the preliminary results of this gamma-ray analysis of 3C 397 and PSR J1906+0722.
We report the discovery of PSR J1101-6101, a 62.8 ms pulsar in IGR J11014-6103, a hard X-ray source with a jet and a cometary tail that strongly suggests it is moving away from the center of the supernova remnant (SNR) MSH 11-61A at v>1000 km/s. Two XMM-Newton observations were obtained with the EPIC pn in small window mode, resulting in the measurement of its spin-down luminosity E_dot = 1.36e36 erg/s, characteristic age Tau_c = 116 kyr, and surface magnetic field strength B_s = 7.4e11 G. In comparison to Tau_c, the 10-30 kyr age estimated for MSH 11-61A suggests that the pulsar was born in t…
PSR J1813--1749 has peculiarities that make it a very interesting object of study. It is one of the most energetic and the most scattered pulsar known. It is associated with HESS J1813--178, one of the brightest and most compact TeV sources in the sky. Recently, Ho et al. used archival X-ray Chandra observations separated by more than 10 years and determined that the total proper motion of PSR J1813--1749 is $\sim66$~mas~yr$^{-1}$, corresponding to a velocity of $\sim$1900 km s$^{-1}$ for a distance of 6.2 kpc. These results would imply that this pulsar is the fastest neutron star known in the…
We present a study on the gamma-ray emission detected by the AGILE-GRID from the region of the SNR G78.2+2.1 (Gamma Cygni). In order to investigate the possible presence of gamma rays associated with the SNR below 1 GeV, it is necessary to analyze the gamma-ray radiation underlying the strong emission from the pulsar PSR J2021+4026, which totally dominates the field. An "off-pulse" analysis has been carried out, by considering only the emission related to the pulsar off-pulse phase of the AGILE-GRID light curve. We found that the resulting off-pulsed emission in the region of the SNR - detecte…
We report the detection of high energy gamma-ray emission from the young and energetic pulsar PSR B1509$-$58 and its pulsar wind nebula (PWN) in the composite supernova remnant SNR G320.4-1.2 (aka MSH 15-52). Using 1 year of survey data with the Fermi-Large Area Telescope (LAT), we detected pulsations from PSR B1509-58 up to 1 GeV and extended gamma-ray emission above 1 GeV spatially coincident with the PWN. The pulsar light curve presents two peaks offset from the radio peak by phases 0.96 $\pm$ 0.01 and 0.33 $\pm$ 0.02. New constraining upper limits on the pulsar emission are derived below 1…
Since its launch in 1990, HST has played a leading role in optical studies of isolated neutron stars, both radio-loud pulsars and radio-silent ones, paving the way to follow-up observations performed with 8m-class telescopes, like the VLT, the Gemini, and Subaru. Here, I present the last results obtained mostly by the WFPC2, before its de-commissioning during the last refurbishment mission in May 2009, from the observations of the rotation-powered pulsars PSR B0540-69, PSR B1055-52 and of the CCO 1E 1207.4-5209 in the PKS 1209-52 SNR.
PSR J0855-4644 is an energetic pulsar (Edot = 1.1x10^36 erg/s, P=65 ms) discovered near the South-East rim of the supernova remnant (SNR) RX J0852.0-4622 (aka Vela Jr) by the Parkes Multibeam Survey. The position of the pulsar is in spatial coincidence with an enhancement in X-rays and TeV gamma-rays, which could represent its pulsar wind nebula (PWN). We have revealed with an XMM-Newton observation the X-ray counterpart of the pulsar together with a surrounding extended emission thus confirming the suggestion of a PWN. The comparison of the absorption column density derived in X-rays from the…
An analysis of arrival directions of extensive air showers (EAS) registered with the EAS MSU and EAS-1000 prototype arrays has revealed a region of excessive flux of PeV cosmic rays in the direction toward pulsars PSR J1840+5640 and LAT PSR J1836+5925 at significance level up to 4.5sigma. The first of the pulsars was discovered almost 30 years ago and is a well-studied old radio pulsar located at the distance of 1.7pc from the Solar system. The second pulsar belongs to a new type of pulsars, discovered by the space gamma-ray observatory Fermi, pulsations of which are not observed in optical an…
We report the detection of the pulsed signal of the radio-quiet magnetar-like pulsar PSR J1846-0258 in the high-energy \gr-ray data of the Fermi Large Area Telescope (Fermi LAT). We produced phase-coherent timing models exploiting RXTE PCA and Swift XRT monitoring data for the post- (magnetar-like) outburst period from 2007 August 28 to 2016 September 4, with independent verification using INTEGRAL ISGRI and Fermi GBM data. Phase-folding barycentric arrival times of selected Fermi LAT events from PSR J1846-0258, resulted in a 4.2 sigma detection (30--100 MeV) of a broad pulse consistent in sha…
Based on its energy-dependent morphology the initially unidentified very high energy (VHE; E>100 GeV) gamma-ray source HESS J1303-631 was recently associated with the pulsar PSR J1301-6305. Subsequent detection of X-ray and GeV counterparts also supports the identification of the H.E.S.S. source as evolved pulsar wind nebula (PWN). We report here on recent radio observations of the PSR J1301-6305 field of view (FOV) with ATCA dedicated to search for the radio counterpart of this evolved PWN. Observations at 5.5 GHz and 7.5 GHz do not reveal any extended emission associated with the pulsar. The…
PSR B1259-63 is a $γ$-ray binary system, where the compact object is a pulsar. The system has an orbital period of 1236.7 days and shows peculiar $γ$-ray flares (in 100\,MeV--300\,GeV) after its periastron time. We analyzed the \textit{Fermi}-LAT observation of PSR B1259-63 during its latest periastron passage, as well as its previous three periastrons. The bright GeV flares started about 60 days after the periastron epoch in 2021. This delay is larger than that around the 2017 periastron and much larger than earlier periastrons. The delay of the GeV flux peak time in each periastron passage i…
Considering about seven years of Fermi-Large Area Telescope (LAT) data, we present a systematic search for variability possibly related to transitions between states in redbacks and black widow systems. Transitions are characterized by sudden and significant changes in the gamma-ray flux that persist on a timescale much larger than the orbital period. This phenomenology was already detected in the case of two redback systems, PSR J1023+0038 and PSR J1227-4853, for which we present here a dedicated study. We show the existence of only one transition for each of these systems over the past seven…
Radio observations of the region surrounding PSR J1301-6305 at 5.5 GHz and 7.5 GHz were conducted with ATCA on September 5th, 2013. They were dedicated to the search of the radio counterpart of the evolved pulsar wind nebula HESS J1303-631, detected in X-rays and GeV-TeV gamma-rays. The collected data do not reveal any significant extended emission associated with PSR J1301-6305. In addition, archival 1.384 GHz and 2.368 GHz data do not show any evidence for a radio counterpart of HESS J1303-631. Archival 1.384 GHz observations reveal a detection of an extended structure centred at an angular …
We report the detection of giant pulse emission from PSR B0950+08 in 24 hours of observations made at 39.4 MHz, with a bandwidth of 16 MHz, using the first station of the Long Wavelength Array, LWA1. We detected 119 giant pulses from PSR B0950+08 (at its dispersion measure), which we define as having SNRs at least 10 times larger than for the mean pulse in our data set. These 119 pulses are 0.035% of the total number of pulse periods in the 24 hours of observations. The rate of giant pulses is about 5.0 per hour. The cumulative distribution of pulse strength $S$ is a steep power law, $N(>S)\pr…
The Fermi Large Area Telescope (LAT) data have confirmed the pulsed emission from all six high-confidence gamma-ray pulsars previously known from the EGRET observations. We report results obtained from the analysis of 13 months of LAT data for three of these pulsars (PSR J1057-5226, PSR J1709-4429, and PSR J1952+3252) each of which had some unique feature among the EGRET pulsars. The excellent sensitivity of LAT allows more detailed analysis of the evolution of the pulse profile with energy and also of the variation of the spectral shape with phase. We measure the cutoff energy of the pulsed e…
PSR J0205+6449 is a young rotation-powered pulsar in SNR 3C 58. It is one of only three young (<10,000 year old) pulsars which are so far detected in the radio and the classical X-ray bands, as well as at hard X-rays above 20 keV and at high-energy (>100 MeV) $γ$-rays. The other two young pulsars are the Crab and PSR B1509-58. Our aim is to derive the timing and spectral characteristics of PSR J0205+6449 over the broad X-ray band from ~0.5 to ~270 keV. We used all publicly available RXTE observations of PSR J0205+6449 to first generate accurate ephemerides over the period September 30, 2000 - …
We report the detection of gamma-ray pulsations (> 0.1 GeV) from PSR J2229+6114 and PSR J1048-5832, the latter having been detected as a low-significance pulsar by EGRET. Data in the gamma-ray band were acquired by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope, while the radio rotational ephemerides used to fold the gamma-ray light curves were obtained using the Green Bank Telescope, the Lovell telescope at Jodrell Bank, and the Parkes telescope. The two young radio pulsars, located within the error circles of the previously unidentified EGRET sources 3EG J1048-5840 and 3…
We report the results of X-ray (CXO) and radio (ATCA) observations of the pulsar wind nebula (PWN) powered by the young pulsar PSR J1016--5857, which we dub "the Goose" PWN. In both bands the images reveal a tail-like PWN morphology which can be attributed to pulsar's motion. By comparing archival and new CXO observations, we measure the pulsar's proper motion $μ=28.8\pm7.3$ mas/yr, yielding a projected pulsar velocity $v \approx 440\pm110$ km/s (at d=3.2 kpc); its direction is consistent with the PWN shape. Radio emission from the PWN is polarized, with the magnetic field oriented along the p…
CTB 80 (G69.0+2.7) is a relatively old (50--80 kyr) supernova remnant (SNR) with a complex radio morphology showing three extended radio arms and a radio and X-ray nebula near the location of the pulsar PSR B1951+32. We report on a study of the GeV emission in the region of CTB 80 with \emph{Fermi}-LAT data. An extended source with a size of 1.3$^\circ$, matching the size of the infrared shell associated to the SNR, was discovered. The GeV emission, detected up to an energy of $\sim 20$ GeV, is more significant at the location of the northern radio arm where previous observations imply that th…
Supernova remnants (SNRs) are among the strongest candidates to explain the flux of cosmic rays below the knee around 10^15 eV. Pulsar wind nebulae (PWNe), synchrotron nebulae powered by the spin-down of energetic young pulsars, comprise one of the most populous VHE gamma-ray source classes. Gamma-ray studies in the GeV and TeV bands probe the nature (ions vs. electrons), production, and diffusion of high-energy particles in SNRs and PWNe. For sources that are visible across both the GeV and TeV bands, such as IC 443, the spatial and spectral distribution of gamma rays can be studied over an u…
PSR B1259-63/LS 2883 is a gamma-ray binary system containing a radio pulsar in a highly elliptical ~3.4-year orbit around a Be star. In its 2010 periastron passage, multiwavelength emission from radio to TeV was observed, as well as an unexpected GeV flare measured by the Fermi Large Area Telescope (LAT). Here, we report the results of LAT monitoring of PSR B1259-63 during its most recent 2014 periastron passage. We compare the gamma-ray behavior in this periastron with the former in 2010 and find that PSR B1259-63 shows a recurrent GeV flare. The similarities and differences in the phenomenol…
We report a discovery of diffuse X-ray emission around the supernova remnant (SNR) G106.3+2.7, which is associated with VER J2227+608 and HAWC J2227+610 and is known as a candidate for a PeV cosmic ray accelerator (PeVatron). We analyze observational data of Suzaku around the SNR and the adjacent pulsar PSR J2229+6114. We find diffuse X-ray emission that is represented by either thermal or non-thermal one. However, the metal abundance for the thermal emission is <0.13 Z_sun, which may be too small in the Milky Way and suggests that the emission is non-thermal. The intensity of the diffuse emis…
We carry out high-energy studies of the region of the Galactic TeV source 3HWC J1954+286, whose location coincides with those of PSR~J1954+2836 and supernova remnant (SNR) G65.1+0.6. Analyzing the GeV $γ$-ray data obtained with the Large Area Telescope (LAT) onboard {\it the Fermi Gamma-ray Space Telescope}, we are able to separate the pulsar's emission from that of the region. Excess power-law--like emission of a $\sim 6σ$ significance level at the region is found, for which we explain as arising from the SNR~G65.1+0.6. Given the low-significance detection, either a hadronic or a leptonic mod…
Supernova Remnants (SNRs) are believed to be acceleration sites of Galactic cosmic rays. Therefore, deep studies of these objects are instrumental for an understanding of the high energy processes in our Galaxy. RX J0852.0-4622, also known as Vela Junior, is one of the few (4) shell-type SNRs resolved at Very High Energies (VHE; E > 100 GeV). It is one of the largest known VHE sources (~ 1.0 deg radius) and its flux level is comparable to the flux level of the Crab Nebula in the same energy band. These characteristics allow for a detailed analysis, shedding further light on the high-energy pro…
Fermi-LAT View on Three Ultra-high-energy 1LHAASO Sources in the $52^{\circ}<l<55^{\circ}$ Region
Yunnan Observatories, Chinese Academy of Sciences（中国科学院云南天文台）；University of Chinese Academy of Sciences（中国科学院大学）；IRAP, Université de Toulouse, CNRS, UPS, CNES（图卢兹大学IRAP研究所）
The source HESS J1813-178 was detected in the survey of the inner Galaxy in TeV gamma-rays, and a SNR G12.8-0.0 was identified in the radio band to be associated with it. The PWN embedded in the SNR is powered by an energetic pulsar PSR J1813-1749, which was recently discovered. Whether the TeV gamma-rays originate from the SNR shell or the PWN is uncertain now. We investigate theoretically the multiwavelength nonthermal radiation from the composite SNR G12.8-0.0. The emission from the particles accelerated in the SNR shell is calculated based on a semianalytical method to the nonlinear diffus…
We performed deep observations to search for radio pulsations in the directions of 375 unassociated Fermi Large Area Telescope (LAT) gamma-ray sources using the Giant Metrewave Radio Telescope (GMRT) at 322 and 607 MHz. In this paper we report the discovery of three millisecond pulsars (MSPs), PSR J0248+4230, PSR J1207$-$5050 and PSR J1536$-$4948. We conducted follow up timing observations for around 5 years with the GMRT and derived phase coherent timing models for these MSPs. PSR J0248$+$4230 and J1207$-$5050 are isolated MSPs having periodicities of 2.60 ms and 4.84 ms. PSR J1536-4948 is a …
The main goal of this paper is to provide new insights on the origin of the observable flux of gamma rays from HESS J1809-193 using new high-quality observations in the radio domain. We used the Expanded Very Large Array (now known as the Karl G. Jansky Very large Array, JVLA) to produce a deep full-synthesis imaging at 1.4 GHz of the vicinity of PSR J1809-1917. These data were used in conjunction with 12CO observations from the James Clerk Maxwell Telescope in the transition line J=3-2 and atomic hydrogen data from the Southern Galactic Plane Survey to investigate the properties of the inters…
