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  • Ge, Ming-Yu  (7)
  • Unknown  (7)
  • 1
    Online Resource
    Online Resource
    An Insight-HXMT Dedicated 33 day Observation of SGR J1935+2154. I. Burst Catalog
    American Astronomical Society ; 2022
    In:  The Astrophysical Journal Supplement Series Vol. 260, No. 2 ( 2022-06-01), p. 24-
    Details
    In: The Astrophysical Journal Supplement Series, American Astronomical Society, Vol. 260, No. 2 ( 2022-06-01), p. 24-
    Abstract: Magnetars are neutron stars with an extreme magnetic field and sometimes manifest as soft gamma-ray repeaters (SGRs). SGR J1935+2154 is one of the most prolific bursters and the first confirmed source of a fast radio burst (FRB; i.e., FRB 200428). Encouraged by the discovery of the first X-ray counterpart of FRBs, the Insight-Hard X-ray Modulation Telescope (Insight-HXMT) implemented a dedicated 33-day-long Target of Opportunity observation of SGR J1935+2154 since 2020 April 28. With the HE, ME, and LE telescopes, Insight-HXMT provides a thorough monitoring of burst activity evolution of SGR J1935+2154, in a very broad energy range (1–250 keV) with high temporal resolution and high sensitivity, resulting in a unique valuable data set for detailed studies of SGR J1935+2154. In this work, we conduct a comprehensive analysis of this observation, including detailed burst search, identification, and temporal analyses. After carefully removing false triggers, we find a total of 75 bursts from SGR J1935+2154, out of which 70 are single pulsed. The maximum burst rate is about 56 bursts day −1 . Both the burst duration and the waiting time between two successive bursts follow lognormal distributions, consistent with previous studies. We also find that bursts with longer duration (some are multipulsed) tend to occur during the period with relatively high burst rate. There is no correlation between the waiting time and the fluence or duration of either the former or latter burst. It also seems that there is no correlation between burst duration and hardness ratio, in contrast to some previous reports. In addition, we do not find any X-ray burst associated with any reported radio bursts except for FRB 200428.
    Type of Medium: Online Resource
    ISSN: 0067-0049 , 1538-4365
    URL: Article
    DOI: 10.3847/1538-4365/ac6172
    RVK:
    UA 1000
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2022
    detail.hit.zdb_id: 2006860-8
    detail.hit.zdb_id: 2207650-5
    SSG: 16,12
    Location Call Number Limitation Availability
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    Online Resource
  • 2
    Online Resource
    Online Resource
    An Insight-HXMT Dedicated 33 day Observation of SGR J1935+2154. II. Burst Spectral Catalog
    American Astronomical Society ; 2022
    In:  The Astrophysical Journal Supplement Series Vol. 260, No. 2 ( 2022-06-01), p. 25-
    Details
    In: The Astrophysical Journal Supplement Series, American Astronomical Society, Vol. 260, No. 2 ( 2022-06-01), p. 25-
    Abstract: Since 2020 April 28, Insight-HXMT has implemented a dedicated observation on the magnetar SGR J1935+2154. Thanks to the wide energy band (1–250 keV) and high sensitivity of Insight-HXMT, we obtained 75 bursts from SGR J1935+2154 during a month-long activity episode after the emission of FRB 200428. Here we report the detailed time-integrated spectral analysis of these bursts and the statistical distribution of the spectral parameters. We find that for ∼15% (11/75) of SGR J1935+2154 bursts, the CPL model is preferred, and most of them occurred in the later part of this active epoch. In the cumulative fluence distribution, we find that the fluence of bursts in our sample is about an order of magnitude weaker than that of Fermi/GBM, but it follows the same power-law distribution. Finally, we find a burst with similar peak energy to the time-integrated spectrum of the X-ray burst associated with FRB 200428 (FRB 200428-Associated Burst), but the low energy index is harder.
    Type of Medium: Online Resource
    ISSN: 0067-0049 , 1538-4365
    URL: Article
    DOI: 10.3847/1538-4365/ac67e4
    RVK:
    UA 1000
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2022
    detail.hit.zdb_id: 2006860-8
    detail.hit.zdb_id: 2207650-5
    SSG: 16,12
    Location Call Number Limitation Availability
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    Online Resource
  • 3
    Online Resource
    Online Resource
    Timing analysis of the black hole candidate EXO 1846–031 with Insight-HXMT monitoring
    IOP Publishing ; 2021
    In:  Research in Astronomy and Astrophysics Vol. 21, No. 3 ( 2021-04-01), p. 070-
    Details
    In: Research in Astronomy and Astrophysics, IOP Publishing, Vol. 21, No. 3 ( 2021-04-01), p. 070-
    Abstract: We present the observational results from a detailed timing analysis of the black hole candidate EXO 1846–031 during its outburst in 2019 with the observations of Insight -HXMT, NICER and MAXI . This outburst can be classified roughly into four different states. Type-C quasi-periodic oscillations (QPOs) observed by NICER (about 0.1–6 Hz) and Insight -HXMT (about 0.7–8 Hz) are also reported in this work. Meanwhile, we study various physical quantities related to QPO frequency. The QPO rms–frequency relationship in the energy band 1–10 keV indicates that there is a turning pointing in frequency around 2 Hz, which is similar to that of GRS 1915+105. A possible hypothesis for the relationship above may be related to the inclination of the source, which may require a high inclination to explain it. The relationships between QPO frequency and QPO rms, hardness, total fractional rms and count rate have also been found in other transient sources, which can indicate that the origin of type–C QPOs is non-thermal.
    Type of Medium: Online Resource
    ISSN: 1674-4527
    URL: Article
    DOI: 10.1088/1674-4527/21/3/70
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2021
    detail.hit.zdb_id: 2511247-8
    SSG: 6,25
    SSG: 16,12
    Location Call Number Limitation Availability
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  • 4
    Online Resource
    Online Resource
    The First Insight-HXMT Gamma-Ray Burst Catalog: The First Four Years
    American Astronomical Society ; 2022
    In:  The Astrophysical Journal Supplement Series Vol. 259, No. 2 ( 2022-04-01), p. 46-
    Details
    In: The Astrophysical Journal Supplement Series, American Astronomical Society, Vol. 259, No. 2 ( 2022-04-01), p. 46-
    Abstract: The Hard X-ray Modulation Telescope (Insight-HXMT) is China’s first X-ray astronomy satellite. It was launched on 2017 June 15. The anticoincidence CsI detectors of the High Energy X-ray telescope (HE) on board Insight-HXMT could serve as an all-sky gamma-ray monitor in about 0.2–3 MeV. In its first four years of operation, Insight-HXMT has detected 322 gamma-ray bursts (GRBs) by the offline search pipeline, including blind search and targeted search. For the GOLDEN sample of Insight-HXMT GRBs, joint analyses were performed with other GRB missions, including the Fermi Gamma-ray Burst Monitor (Fermi/GBM), the Swift Burst Alert Telescope (Swift/BAT), and the Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM). The analyses showed that Insight-HXMT can provide a better constraint on the GRB spectrum at a higher-energy band. The properties of Insight-HXMT GRBs are reported in detail, including their trigger time, duration, spectral parameters, peak fluxes of different timescales, and fluence. This catalog is an official product of the Insight-HXMT GRB team.
    Type of Medium: Online Resource
    ISSN: 0067-0049 , 1538-4365
    URL: Article
    DOI: 10.3847/1538-4365/ac4d22
    RVK:
    UA 1000
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2022
    detail.hit.zdb_id: 2006860-8
    detail.hit.zdb_id: 2207650-5
    SSG: 16,12
    Location Call Number Limitation Availability
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  • 5
    Online Resource
    Online Resource
    Neutral Atmospheric Density Measurement Using Insight-HXMT Data by the Earth Occultation Technique
    American Astronomical Society ; 2023
    In:  The Astrophysical Journal Supplement Series Vol. 264, No. 1 ( 2023-01-01), p. 5-
    Details
    In: The Astrophysical Journal Supplement Series, American Astronomical Society, Vol. 264, No. 1 ( 2023-01-01), p. 5-
    Abstract: The Earth occultation technique has broad applications in both astronomy and atmospheric density measurements. We construct the background model during the occultation of the Crab Nebula observed by the Insight-Hard X-ray Modulation Telescope (Insight-HXMT) at energies between 6 and 100 keV. We propose a Bayesian atmospheric density retrieval method based on the Earth occultation technique, combining Poisson and Gaussian statistics. By modeling the atmospheric attenuation of X-ray photons during the occultation, we simultaneously retrieved the neutral densities of the atmosphere at different altitude ranges. Our method considers the correlation of densities between neighboring atmospheric layers and reduces the potential systematic bias to which previous work may be subject. Previous analyses based on light-curve fitting or spectral fitting also lost some spectral or temporal information of the data. In contrast to previous work, the occultation data observed by the three telescopes on board Insight-HXMT is fully used in our analysis, further reducing the statistical error in density retrieval. We apply our method to cross-check the (semi)empirical atmospheric models, using 115 sets of occultation data of the Crab Nebula observed by Insight-HXMT. We find that the retrieved neutral density is ∼10%, ∼20%, and ∼25% less than the values of the widely used atmospheric model NRLMSISE-00, in the altitude range of 55–80 km, 80–90 km, and 90–100 km, respectively. We also show that the newly released atmospheric model NRLMSIS 2.0 is generally consistent with our density measurements.
    Type of Medium: Online Resource
    ISSN: 0067-0049 , 1538-4365
    URL: Article
    DOI: 10.3847/1538-4365/ac9f16
    RVK:
    UA 1000
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2023
    detail.hit.zdb_id: 2006860-8
    detail.hit.zdb_id: 2207650-5
    SSG: 16,12
    Location Call Number Limitation Availability
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    Online Resource
  • 6
    Online Resource
    Online Resource
    The Minimum Variation Timescales of X-Ray Bursts from SGR J1935+2154
    American Astronomical Society ; 2023
    In:  The Astrophysical Journal Supplement Series Vol. 268, No. 1 ( 2023-09-01), p. 5-
    Details
    In: The Astrophysical Journal Supplement Series, American Astronomical Society, Vol. 268, No. 1 ( 2023-09-01), p. 5-
    Abstract: The minimum variation timescale (MVT) of soft gamma-ray repeaters can be an important probe to estimate the emission region in pulsar-like models, as well as the Lorentz factor and radius of the possible relativistic jet in gamma-ray burst (GRB)–like models, thus revealing their progenitors and physical mechanisms. In this work, we systematically study the MVTs of hundreds of X-ray bursts (XRBs) from SGR J1935+2154 observed by Insight-HXMT, GECAM, and Fermi/Gamma-ray Burst Monitor from 2014 July to 2022 January through the Bayesian block algorithm. We find that the MVTs peak at ∼2 ms, corresponding to a light-travel time size of about 600 km, which supports the magnetospheric origin in pulsar-like models. The shock radius and the Lorentz factor of the jet are also constrained in GRB-like models. Interestingly, the MVT of the XRB associated with FRB 200428 is ∼70 ms, which is longer than that of most bursts and implies its special radiation mechanism. In addition, the median of MVTs is 7 ms, shorter than the median MVTs of 40 ms and 480 ms for short GRBs or long GRBs, respectively. However, the MVT is independent of duration, similar to GRBs. Finally, we investigate the energy dependence of MVT and suggest that there is a marginal evidence for a power-law relationship like GRBs, but the rate of variation is at least about an order of magnitude smaller. These features may provide an approach to identify bursts with a magnetar origin.
    Type of Medium: Online Resource
    ISSN: 0067-0049 , 1538-4365
    URL: Article
    DOI: 10.3847/1538-4365/ace77c
    RVK:
    UA 1000
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2023
    detail.hit.zdb_id: 2006860-8
    detail.hit.zdb_id: 2207650-5
    SSG: 16,12
    Location Call Number Limitation Availability
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    Online Resource
  • 7
    Online Resource
    Online Resource
    Pulsar and Magnetar Navigation with Fermi/GBM and GECAM
    American Astronomical Society ; 2023
    In:  The Astrophysical Journal Supplement Series Vol. 266, No. 1 ( 2023-05-01), p. 16-
    Details
    In: The Astrophysical Journal Supplement Series, American Astronomical Society, Vol. 266, No. 1 ( 2023-05-01), p. 16-
    Abstract: The determination of the absolute and relative position of a spacecraft is critical for its operation, observations, data analysis, scientific studies, as well as deep-space exploration in general. A spacecraft that can determine its own absolute position autonomously may perform better than those that must rely on transmission solutions. In this work, we report an absolute navigation accuracy of ∼20 km using 16 day Crab pulsar data observed with Fermi’s Gamma-ray Burst Monitor (GBM). In addition, we propose a new method with the inverse process of the triangulation for joint navigation using repeated bursts like those from the magnetar SGR J1935+2154 observed by the Gravitational-wave High-energy Electromagnetic Counterpart All-sky Monitor and GBM.
    Type of Medium: Online Resource
    ISSN: 0067-0049 , 1538-4365
    URL: Article
    DOI: 10.3847/1538-4365/acc79d
    RVK:
    UA 1000
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2023
    detail.hit.zdb_id: 2006860-8
    detail.hit.zdb_id: 2207650-5
    SSG: 16,12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
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