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We present a spectrum of Sgr A* observed simultaneously on June 17, 2003 at wavelengths from 90 to 0.7 cm with the VLA. In the spectrum, we also include the measurements of Sgr A* observed on the same day with the GMRT at 49 cm, the SMA at…

Astrophysics · Physics 2007-05-23 T. An , J. -H. Zhao , X. -Y. Hong , Z. -Q. Shen , W. M. Goss , S. Roy , A. P. Rao

We present multi-frequency and high-resolution studies of a sample of 24 radio transients sources discovered by comparing the NRAO VLA Sky Survey (NVSS) and Very Large Array Sky Survey (VLASS) surveys. All of them are characterized by a…

Astrophysics of Galaxies · Physics 2024-12-11 M. Kunert-Bajraszewska , A. Krauze , A. E. Kimball , L. Stawarz , P. Kharb , D. Stern , K. Mooley , K. Nyland , D. Koziel-Wierzbowska

Blazars are characterized by large amplitude and fast variability, indicating that the electron distribution is rapidly changing, often on time scales shorter than the light crossing time. We study the time dependent behavior of the…

Astrophysics · Physics 2007-05-23 Marco Chiaberge , Gabriele Ghisellini

We present the long-term spectro-temporal evolution of the average radio emission properties of the magnetar XTE J1810-197 (PSR J1809-1943) following its most recent outburst in late 2018. We report the results from two and a half years of…

High Energy Astrophysical Phenomena · Physics 2022-06-01 Yogesh Maan , Mayuresh P. Surnis , Bhal Chandra Joshi , Manjari Bagchi

Blazars are characterized by large amplitude and fast variability, indicating that the electron distribution is rapidly changing, often on time scales shorter than the light crossing time. The emitting region is sufficiently compact to let…

Astrophysics · Physics 2009-10-31 Marco Chiaberge , Gabriele Ghisellini

In this paper we present the first observations of a large sample of millisecond pulsars at frequencies of 2.7 GHz and 4.9 GHz. Our new flux measurements extend the known spectra for millisecond pulsars to the highest frequencies to date.…

Astrophysics · Physics 2009-10-31 M. Kramer , C. Lange , D. R. Lorimer , D. C. Backer , K. M. Xilouris , A. Jessner , R. Wielebinski

We have measured 21-cm absorption spectra in the direction of three southern pulsars, PSRs B0736-40, B1451-68 and B1641-45, in three separate epochs spread over 2.5 yr. We see no evidence for any changes in the absorption spectra over this…

Astrophysics · Physics 2009-11-07 Simon Johnston , Baerbel Koribalski , Warwick Wilson , Mark Walker

The observed spectra of 9 pulsars for which multiwavelength data are available from radio to $X$- or $\gamma$-ray bands (Crab, Vela, Geminga, B0656+14, B1055-52, B1509-58, B1706-44, B1929+10, and B1951+32) are compared with the spectrum of…

Astrophysics of Galaxies · Physics 2009-08-11 H. Ardavan , A. Ardavan , J. Singleton , J. Fasel , W. Junor , J. Middleditch , M. R. Perez , A. Schmidt , P. Sengupta , P. Volegov

The dynamic spectrum of a radio pulsar is an in-line digital hologram of the ionised interstellar medium. It has previously been demonstrated that such holograms permit image reconstruction, in the sense that one can determine an…

Astrophysics · Physics 2009-11-13 Mark Walker , Leon Koopmans , Dan Stinebring , Willem van Straten

Gravitational waves (GWs) can offer a novel window into the structure and dynamics of neutron stars. Here we present the first search for long-duration quasi-monochromatic GW transients triggered by pulsar glitches. We focus on two glitches…

We have observed pulsar wind nebulae in the three supernova remnants G11.2-0.3, G16.7+0.1, and G29.7-0.3 at 89 GHz with the Berkeley-Illinois-Maryland Association Array, measuring total flux densities of two of them for comparison with…

Astrophysics · Physics 2009-11-10 D. C. -J. Bock , B. M. Gaensler

Detecting and studying pulsars above a few GHz in the radio band is challenging due to the typical faintness of pulsar radio emission, their steep spectra, and the lack of observatories with sufficient sensitivity operating at high…

High Energy Astrophysical Phenomena · Physics 2018-06-29 Pablo Torne

The radio continuum spectra of pulsars (PSRs) exhibit a wide variety of shapes, that are interpreted as pure and broken power laws, power laws with turnovers or cut-offs, and logarithmic-parabolic profiles. A notable fraction of these have…

Astrophysics of Galaxies · Physics 2025-11-24 Mario G. Abadi , Gabriela Castelletti , Namir E. Kassim

We have observed the 5.54s anomalous X-ray pulsar XTE J1810-197 at radio, millimeter, and infrared (IR) wavelengths, with the aim of learning about its broad-band spectrum. At the IRAM 30m telescope, we have detected the magnetar at 88 and…

We present the results of flux density monitoring of PSR B0329+54 at the frequency of 4.8 GHz using the 32-meter TCfA radiotelescope. The observations were conducted between 2002 and 2005. The main goal of the project was to find…

Astrophysics of Galaxies · Physics 2015-05-28 Wojciech Lewandowski , Jaroslaw Kijak , Yashwant Gupta , Krzysztof Krzeszowski

Pulsars are known for their exceptionally stable rotation. However, this stability can be disrupted by glitches, sudden increases in rotation frequency whose cause is poorly understood. In this study, we present some preliminary results…

Studies of the pulsar B0823+26 have been carried out using the Large Phased Array (LPA) radio telescope. At time span of 5.5 years, the amplitudes of the main pulse (MP), postcursor (PC) and interpulse (IP) were evaluated in daily sessions…

High Energy Astrophysical Phenomena · Physics 2023-11-10 M. O. Toropov , S. A. Tyul'bashev , T. V. Smirnova , V. A. Samodurov , I. L. Ovchinnikov

We detected X-ray emission from PSR B1800-21 and its synchrotron nebula with the Chandra X-ray Observatory. The pulsar's observed flux is (1.4+/-0.2) 10^{-14} ergs cm^{-2} s^{-1} in the 1-6 keV band. The spectrum can be described by a…

Astrophysics · Physics 2011-02-11 O. Kargaltsev , G. G. Pavlov , G. P. Garmire

Pulsars with periods more than 0.4 seconds in the declination range -9o < decj < 42o and in the right ascension range 0h < r.a.< 24h were searched in parallel with the program of interplanetary scintillations monitoring of a large number of…

We report on analysis of timing and spectroscopy of the Vela pulsar using eleven months of observations with the Large Area Telescope on the Fermi Gamma-Ray Space Telescope. The intrinsic brightness of Vela at GeV energies combined with the…

High Energy Astrophysical Phenomena · Physics 2015-05-18 A. A. Abdo