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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

10363 results found.

  1. Fermi trigger No 763509110: Global MASTER-Net observations report
  2. GRB 250312B: Fermi GBM Final Localization
  3. LIGO/Virgo/KAGRA S250304cb: Upper limits from Swift/BAT-GUANO
  4. GRB 250312A: Swift detection of a burst
  5. GRB 230509B: 1.3m DFOT Optical observations
  6. GRB 250308A: Swift/BAT-GUANO localization skymap of a short burst
  7. GRB 250302A: Swift/BAT-GUANO localization skymap of a burst
  8. GRB 250228A: Swift/BAT-GUANO localization skymap of a likely short burst
  9. GRB 250226B: Swift/BAT-GUANO localization skymap of a likely long GRB
  10. GRB 250226A: Swift/BAT-GUANO localization skymap of a long GRB
  11. GRB 250223B: Swift/BAT-GUANO localization skymap of a short burst
  12. GRB 250309B: PRIME near-infrared detection
  13. GRB 250311A/EP250311a: TRT optical upper limit
  14. EP250311a/GRB 250311A: EP-WXT detection
  15. GRB 250311A/MAXI J1457-026: MAXI/GSC detection
  16. Konus-Wind detection of GRB 250309B
  17. IPN triangulation of GRB 250308A (short)
  18. IceCube-241224A: MASTER detection of PKS 1217+02 blazar flare with Zhirkov effect
  19. GRB 250309B: Swift-XRT refined Analysis
  20. GRB 250309B / AT2025dws: Swift-UVOT detection
  21. Fermi GRB 250309A: Global MASTER-Net observations report
  22. Fermi-LAT gamma-ray observations of IceCube-250309A
  23. IceCube Alert 250309.32: Global MASTER-Net observations report
  24. EP250308a: Einstein Probe detection of an X-ray transient
  25. The EP-WXT trigger 01709132387 is likely a flaring star
  26. Fermi GRB 250307A: Global MASTER-Net observations report
  27. Konus-Wind detection of GRB 250306A
  28. IceCube-241016A: MASTER flaring blazar 5BZU J073038.29-320820.2 with Zhirkov effect
  29. GRB 250305A: AstroSat CZTI detection
  30. GRB 250306A: AstroSat CZTI detection
  31. Fermi trigger No 762963055: Global MASTER-Net observations report
  32. LIGO/Virgo/KAGRA S250207bg: Update-5 NED Galaxies in the Localization Volume
  33. Fermi-LAT Gamma-ray Observations of IceCube-250302A
  34. EP 250304A: Optical counterpart detection by LCO
  35. EP250302A: 1.3m DFOT optical afterglow detection
  36. IceCube-250302A: Upper limits from a search for additional neutrino events in IceCube
  37. EP250304a: refined analysis of the EP-WXT and EP-FXT observations
  38. Konus-Wind detection of GRB 250222A
  39. EP250304a: Einstein Probe detection of an X-ray transient
  40. EP250302a: SAO RAS optical observations
  41. EP250302a : GIT optical follow-up
  42. EP250302a: optical observation from the INAF Asiago Observatory
  43. IceCube-241113A: MASTER flaring blazar 5BZB J1311+0853 with Zhirkov effect
  44. EP250302A: VLT near-infrared observations
  45. EP250302a: OHP/T193 optical and spectroscopic observations
  46. EP250302a: Einstein Probe detection of an X-ray transient
  47. EP250302a: Montarrenti Observatory optical detection
  48. Fermi GRB 250302A: Global MASTER-Net observations report
  49. EP250302a: FTW optical and NIR detection
  50. IceCube-250302A - IceCube observation of a high-energy neutrino candidate track-like event
  51. EP250228a: Optical observations with Kinder and Swift/UVOT
  52. Konus-Wind detection of GRB 250226A
  53. GRB 250225B: VLT/HAWKI near-infrared observations
  54. EP250227a: Einstein Probe detected of a fast X-ray transient
  55. EP250223a: J band upper limit by SYSU 80cm telescope
  56. EP250228a: Einstein Probe detection of an X-ray transient
  57. GRB 250226B: INTEGRAL SPI-ACS and PICsIT detection
  58. EP250226a/GRB 250226A: refined analysis of the EP-WXT and FXT observations
  59. Konus-Wind detection of GRB 250225B
  60. GRB 250225B: VLT/FORS2 candidate optical afterglow
  61. EP250226a/GRB 250226A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  62. EP250226a / GRB 250226A: TRT optical counterpart observation
  63. LIGO/Virgo S250223dk: Swift XRT observations, 7 X-ray sources
  64. EP250226a/GRB 250226A: EP-WXT detection and FXT follow-up observation of an X-ray transient
  65. Fermi GRB 250226A: Global MASTER-Net observations report
  66. EP250225a: Einstein Probe detected of a fast X-ray transient
  67. Fermi GRB 250225A: Global MASTER-Net observations report
  68. EP250215A: J band upper limit by SYSU 80cm telescope
  69. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: AstroSat CZTI non-detection and upper limits
  70. GRB 250223C: Fermi GBM Final Real-time Localization
  71. GRB 250202B: VZLUSAT-2 detection
  72. GRB 250219A: EP-FXT afterglow detection
  73. EP250223a: 1.6m Mephisto and 50cm array observations
  74. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO trigger with ID 762004910: Identification of a GW compact binary merger candidate possibly associated with a sub-threshold Swift/BAT-GUANO trigger
  75. EP250223a: NOT optical afterglow candidate
  76. Fermi GRB 250223A: Global MASTER-Net observations report
  77. EP250223a: Einstein Probe detection of an X-ray transient
  78. LIGO/Virgo/KAGRA S250206dm: Upper limits from IceCube neutrino searches
  79. GRB 250221A: continued Assy optical observations, brightening afterglow confirmation
  80. Konus-Wind detection of GRB 250221A
  81. GRB 250221A: Assy optical observations
  82. EP250220a: FTW optical and NIR observations and upper limits
  83. EP250220a: EP-FXT follow-up observations
  84. GRB 250221A: Swift-XRT refined Analysis
  85. EP250220a: Liverpool Telescope upper limits
  86. EP250220a: 1.6m Mephisto observations
  87. EP250220a: Liverpool Telescope optical upper limits
  88. GRB 250221A: Swift detection of a burst with an optical counterpart
  89. Swift GRB250221.15: Global MASTER-Net OT detection
  90. Swift GRB250221.15: Global MASTER-Net observations report
  91. Fermi Gamma-ray Burst Monitor trigger 761788229/250220993 is not a GRB
  92. GRB 250220B: Fermi GBM Final Real-time Localization
  93. Fermi Gamma-ray Burst Monitor trigger 761782146/250220923 is not a GRB
  94. GRB 250220A: Fermi GBM Final Real-time Localization
  95. EP250220a: Global MASTER-Net observations report
  96. EP250220a: EP-WXT detection of a fast X-ray transient
  97. Konus-Wind detection of GRB 250217C (short)
  98. GRB 250219A: OHP/T193 optical upper limit
  99. GRB 250219A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  100. Konus-Wind detection of GRB 250215A / EP250215a

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