J/ApJ/931/67 Magnetar XTEJ1810-197 follow-up 300-1450MHz GMRT obs. (Maan+, 2022)
Magnetar XTE J1810-197: spectro-temporal evolution of average radio emission.
Maan Y., Surnis M.P., Joshi B.C., Bagchi M.
<Astrophys. J., 931, 67 (2022)>
=2022ApJ...931...67M 2022ApJ...931...67M
ADC_Keywords: Pulsars; Radio sources
Keywords: Magnetars ; Radio pulsars ; Rotation powered pulsars ;
Neutron stars ; Non-thermal radiation sources ;
Interstellar absorption ; Interstellar medium ;
Radio transient sources ; Radio bursts ; Pulsars ;
Soft gamma-ray repeaters
Abstract:
We present the long-term spectro-temporal evolution of the average
radio emission properties of the magnetar XTE J1810-197
(PSRJ1809-1943), following its most recent outburst in late 2018. We
report the results from a 2.5yr monitoring campaign with the upgraded
Giant Metrewave Radio Telescope, carried out over the frequency range
of 300-1450MHz. Our observations show intriguing time variability in
the average profile width, flux density, spectral index, and broadband
spectral shape. While the average profile width appears to gradually
decrease at later epochs, the flux density shows multiple episodes of
radio rebrightening over the course of our monitoring. Our systematic
monitoring observations reveal that the radio spectrum has steepened
over time, resulting in evolution from a magnetar-like spectrum to a
more pulsar-like spectrum. A more detailed analysis reveals that the
radio spectrum has a turnover, and that this turnover shifts toward
lower frequencies with time. We present the details of our analysis
leading to these results, and discuss our findings in the context of
magnetar radio emission mechanisms, as well as potential
manifestations of the intervening medium. We also briefly discuss
whether an evolving spectral turnover could be a ubiquitous property
of radio magnetars.
Description:
After the successful detection and follow-up of the magnetar
XTEJ1810-197 at a number of epochs in late 2018 and early 2019
(Joshi+ 2018ATel12312....1J 2018ATel12312....1J & Maan+ 2019ApJ...882L...9M 2019ApJ...882L...9M) using the
Director's Discretionary Time allocations, we started a low-frequency
monitoring campaign on this source with the Giant Metrewave Radio
Telescope (GMRT). The monitoring observations utilized bands 3, 4, and
5 of the GMRT, with typical center frequencies of 400, 650, and
1360MHz, respectively, and 200MHz bandwidths at each of the bands.
Objects:
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RA (ICRS) DE Designation(s)
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18 09 51.07 -19 43 51.7 XTE J1810-197 = SWIFT J180951.3-194350
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig2.dat 36 95 Period averaged flux densities
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See also:
B/psr : ATNF Pulsar Catalogue (Manchester+, 2005)
J/A+A/493/339 : XMM-Newton serendipitous Survey. V. (Watson+, 2009)
J/ApJ/756/27 : Classification of sources from the 2XMMi-DR3 cat. (Lin+, 2012)
J/ApJS/212/6 : The McGill magnetar catalog (Olausen+, 2014)
J/A+A/625/A122 : CIELO-RGS, soft X-ray ionized emission lines cat. (Mao+, 2019)
J/A+A/645/A18 : SVOM-ECLAIRs known X-ray sources catalogue (Dagoneau+, 2021)
J/ApJ/916/100 : Galactic pulsar with proper motions (Ronchi+, 2021)
Byte-by-byte Description of file: fig2.dat
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Bytes Format Units Label Explanations
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1- 10 F10.4 d MJD [58470.16/59307.1] Modified Julian Date
12- 18 F7.2 MHz Freq [337.3/1405.7] Frequency
20- 27 E8.2 mJy Flux [0.95/60.5] Flux density
29- 36 E8.2 mJy e_Flux [0.4/30.3] Uncertainty in Flux
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 21-Mar-2024