The X-ray reactivation of the radio bursting magnetar SGR 1935+2154

Borghese, A.; Zelati, F. Coti; Rea, N.; Esposito, P.; Israel, G. L.; Mereghetti, S.; Tiengo, A.

doi:10.48550/arxiv.2006.00215

Cited by 4 publications

(6 citation statements)

References 31 publications

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“…For each X-ray burst, we place the fluence at the frequency corresponding to the peak of the fluence spectrum (= νfν ) observed in the X-rays (and its uncertainty). The estimated fluence peak for bursts A and B are consistent with the observed spectrum of the bursts from NuSTAR observations (Borghese et al 2020), where the fluence is observed to rise up to at least ∼ 20 keV. In the case of burst C and D, the fluence spectrum was not well constrained and hence are placed nominally at 10 keV with error-bars spanning the full HXMT sensitivity range.…”

Section: Comparison To the Multi-wavelength Properties Of Frb 200428supporting

confidence: 78%

“…In order to constrain potential multi-wavelength counterparts, we searched all available public reports of X-ray and radio bursts from the source within our observing time intervals. A total of four X-ray bursts were reported by the HXMT (Li et al 2020b) 3 and NuSTAR (Borghese et al 2020) satellites during our observations. Table 2 provides an overview of the X-ray bursts reported during our observations.…”

Section: Resultsmentioning

confidence: 85%

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Constraining the X-ray - Infrared spectral index of second-timescale flares from SGR1935+2154 with Palomar Gattini-IR

De,

Ashley,

Andreoni

et al. 2020

Preprint

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The Galactic magnetar SGR 1935+2154 has been reported to produce the first known example of a bright millisecond duration radio burst (FRB 200428) similar to the cosmological population of fast radio bursts (FRBs), bolstering the association of FRBs to active magnetars. The detection of a coincident bright X-ray burst has revealed the first observed multi-wavelength counterpart of a FRB. However, the search for similar emission at optical wavelengths has been hampered by the high inferred extinction on the line of sight. Here, we present results from the first search for second-timescale emission from the source at near-infrared wavelengths using the Palomar Gattini-IR observing system in J-band, made possible by a recently implemented detector read-out mode that allowed for short exposure times of ≈ 0.84 s with 99.9% observing efficiency. With a total observing time of ≈ 12 hours (≈ 47728 images) on source during its 2020 outburst, we place median 3 σ limits on the second-timescale emission of 20 mJy (13.1 AB mag). We present non-detection limits from epochs of four simultaneous X-ray bursts detected by the Insight-HXMT and NuSTAR telescopes during our observing campaign. The limits translate to an observed fluence limit of 18 Jy ms, while the corresponding extinction corrected limit is 125 Jy ms for an estimated extinction of A J = 2.0 mag. These limits provide the most stringent constraints (energy 3×10 36 erg at 9 kpc) to date on the fluence of flares at frequencies of ∼ 10 14 Hz, and constrain the ratio of the near-infrared (NIR) fluence to that of coincident X-ray bursts to R NIR 2.5 × 10 −2 . Our observations were sensitive enough to easily detect a near-infrared counterpart of FRB 200428 if the NIR emission falls on the same power law as that observed across its radio to X-ray spectrum. The non-detection of NIR emission around the coincident X-ray bursts constrains the fluence index of the brightest burst to be steeper than ≈ 0.35.

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Section: Comparison To the Multi-wavelength Properties Of Frb 200428supporting

confidence: 78%

Section: Resultsmentioning

confidence: 85%

Constraining the X-ray - Infrared spectral index of second-timescale flares from SGR1935+2154 with Palomar Gattini-IR

De,

Ashley,

Andreoni

et al. 2020

Preprint

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“…At the same time, the source continued to show X-ray bursting activity, albeit with a decreasing frequency and mostly weaker bursts. However some were at least as bright as the one seen concurrently with the radio burst (Borghese et al 2020a). Observations with the Westerbork single 25-m dish RT1 , the Onsala 25-m telescope (L-band, 1360(L-band, -1488, and the Torun 32-m telescope (C-band, 4550-4806 MHz) took place when the source emitted two X-ray bursts with no simultaneous radio detections (Kirsten et al 2020b).…”

mentioning

confidence: 99%

Multifrequency observations of SGR J1935+2154

Bailes

Bassa

Bernardi

et al. 2021

Monthly Notices of the Royal Astronomical Society

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Magnetars are a promising candidate for the origin of Fast Radio Bursts (FRBs). The detection of an extremely luminous radio burst from the Galactic magnetar SGR J1935+2154 on 2020 April 28 added credence to this hypothesis. We report on simultaneous and non-simultaneous observing campaigns using the Arecibo, Effelsberg, LOFAR, MeerKAT, MK2 and Northern Cross radio telescopes and the MeerLICHT optical telescope in the days and months after the April 28 event. We did not detect any significant single radio pulses down to fluence limits between 25 mJy ms and 18 Jy ms. Some observing epochs overlapped with times when X-ray bursts were detected. Radio images made on four days using the MeerKAT telescope revealed no point-like persistent or transient emission at the location of the magnetar. No transient or persistent optical emission was detected over seven days. Using the multi-colour MeerLICHT images combined with relations between DM, NH and reddening we constrain the distance to SGR J1935+2154, to be between 1.5 and 6.5 kpc. The upper limit is consistent with some other distance indicators and suggests that the April 28 burst is closer to two orders of magnitude less energetic than the least energetic FRBs. The lack of single-pulse radio detections shows that the single pulses detected over a range of fluences are either rare, or highly clustered, or both. It may also indicate that the magnetar lies somewhere between being radio-quiet and radio-loud in terms of its ability to produce radio emission efficiently.

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“…Its magnetar nature has been confirmed by the follow-up observations, which revealed the spin period P = 3.24 s, spin-down rate Ṗ = 1.43 × 10 −11 s s −1 , and an in-ferred surface dipole-magnetic field B ∼ 2.2 × 10 14 G (Israel et al 2016). The follow-up observations revealed that this magnetar has several active episodes, making it by far the most prolific magnetar (Younes et al 2017;Lin et al 2020a;Borghese et al 2020). The distance of SGR J1935+2154 is ∼ (2 − 7) kpc, which is estimated from a bright expanding dust-scattering X-ray ring observed by the X-ray Telescope(XRT; Mereghetti et al 2020) onboard Swift.…”

Section: Introductionmentioning

confidence: 61%

Bursts before Burst: A Comparative Study on FRB 200428-associated and FRB-absent X-ray Bursts from SGR J1935+2154

Yang,

Zhang,

Lin

et al. 2020

Preprint

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Accompanied by an X-ray burst, the fast radio burst FRB 200428 was recently confirmed to originate from the Galactic magnetar SGR J1935+2154. Just before FRB 200428 was detected, the Fivehundred-meter Aperture Spherical radio Telescope (FAST) had been monitoring SGR J1935+2154 for eight hours. From UTC 2020-04-27 23:55:00 to 2020-04-28 00:50:37, FAST detected no pulsed radio from SGR J1935+2154, while Fermi/GBM registered 34 SGR bursts in the X/soft γ-ray band, forming a unique sample of X-ray bursts in the absence of FRBs. After a comprehensive analysis on light curves, time-integrated and time-resolved spectral properties of these FRB-absent X-ray bursts, we compare this sample with the FRB-associated X-ray burst detected by Insight-HXMT. The FRB-associated burst distinguishes itself from other X-ray bursts by its non-thermal spectrum and a higher spectral peak energy, but is otherwise not atypical in many other aspects. We also compare the cumulative energy distribution of our X-ray burst sample with the cumulative radio energy distribution of first repeating FRB source, FRB 121102, with the calibration of FRB 200428-X-ray burst association. We find a similarity between the two, offering indirect support of the magnetar-origin of cosmological FRBs. The event rate density of magnetar bursts is about ∼ 150 times higher than the FRB event rate density at the energy of FRB 200428. This again suggests that only a small fraction of X-ray bursts are associated with FRBs if all FRBs originate from magnetars.

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The X-ray reactivation of the radio bursting magnetar SGR 1935+2154

Cited by 4 publications

References 31 publications

Constraining the X-ray - Infrared spectral index of second-timescale flares from SGR1935+2154 with Palomar Gattini-IR

Constraining the X-ray - Infrared spectral index of second-timescale flares from SGR1935+2154 with Palomar Gattini-IR

Multifrequency observations of SGR J1935+2154

Bursts before Burst: A Comparative Study on FRB 200428-associated and FRB-absent X-ray Bursts from SGR J1935+2154

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