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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

46004 results found.

  1. EP250228a: Global MASTER-Net observations report
  2. EP250228a: Einstein Probe detection of an X-ray transient
  3. GRB 250226A / EP250226a: LCO detection of the afterglow
  4. LIGO/Virgo/KAGRA S250227e: Updated Sky localization
  5. LIGO/Virgo/KAGRA S250226dl: Updated Sky localization
  6. GRB 250225B: VLT/Xshooter imaging
  7. GRB 250205A / EP250205A: further radio observations with the VLA
  8. GRB 250226B: INTEGRAL SPI-ACS and PICsIT detection
  9. EP250226a/GRB 250226A: INTEGRAL SPI-ACS and PICsIT detection
  10. GRB 250225B: INTEGRAL SPI-ACS detection
  11. EP250225a: NOT optical candidate counterpart
  12. EP250226a/GRB 250226A:Xinglong optical follow-up observations
  13. EP250226a / GRB 250226A: SVOM/VT optical observations
  14. EP250226a/GRB 250226A: refined analysis of the EP-WXT and FXT observations
  15. EP250225a: TRT optical upper limits
  16. EP250226a/GRB 250226A: 1.6m Mephisto observations
  17. LIGO/Virgo/KAGRA S250206dm: Upper limits from SVOM/GRM Observations
  18. EP250226a/GRB 250226A: Kinder optical follow-up observations
  19. LIGO/Virgo/KAGRA S250223dk: Insight-HXMT/HE sub-threshold detection of a burst (HEB 250223501)
  20. LIGO/Virgo/KAGRA S250227y: Retraction of GW compact binary merger candidate
  21. LIGO/Virgo/KAGRA S250227e: Identification of a GW compact binary merger candidate
  22. Fermi GRB 250226B: Global MASTER-Net observations report
  23. LIGO/Virgo/KAGRA S250226dl: Identification of a GW compact binary merger candidate
  24. GRB 250226B: Fermi GBM Final Real-time Localization
  25. GRB 250225B: Fermi GBM Observation
  26. GRB 250221A: ATCA Detections and Upper Limits
  27. GRB 250225B: REM NIR upper limits
  28. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Updated Sky localization and Coincidence with External Event
  29. Konus-Wind detection of GRB 250225B
  30. LIGO/Virgo/KAGRA S250223dk: DECam optical detections of Swift X-ray sources
  31. EP250223a: CrAO ZTSH optical observation
  32. GRB 250225B: VLT optical and near-infrared candidate counterpart
  33. GRB 250225B: VLT/FORS2 candidate optical afterglow
  34. GRB 250225B: SVOM/GRM observation of a long burst
  35. GRB 250226A: GECAM-B detection
  36. GRB 250221A: EP-FXT detection of the X-ray afterglow
  37. GRB 250214A: SVOM/GRM observation
  38. EP250226a/GRB 250226A: GSP detects optical counterpart
  39. EP250226a/GRB 250226A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  40. EP250226a / GRB 250226A: VLT/X-shooter redshift of z = 3.315
  41. EP250226a / GRB 250226A: TRT optical counterpart observation
  42. LIGO/Virgo S250223dk: Swift XRT observations, 7 X-ray sources
  43. EP250226a: Global MASTER-Net observations report
  44. Swift GRB 250225B: Global MASTER-Net observations report
  45. EP250226a/GRB 250226A: EP-WXT detection and FXT follow-up observation of an X-ray transient
  46. Fermi GRB 250226A: Global MASTER-Net observations report
  47. Fermi trigger No 762205158: Global MASTER-Net observations report
  48. GRB 250226A: Fermi GBM Final Real-time Localization
  49. EP250225a: Global MASTER-Net observations report
  50. EP250225a: GSP optical upper limit
  51. EP250223a: GMG Optical Observation
  52. EP250225a: Einstein Probe detected of a fast X-ray transient
  53. Fermi GRB 250225A: Global MASTER-Net observations report
  54. GRB 250225B: Swift detection of a burst
  55. EP250223a: GROWTH-India Telescope optical observations
  56. GRB 250221A: Swift-BAT refined analysis
  57. GRB 250223C: SVOM/GRM observation of a long burst
  58. EP250215A: J band upper limit by SYSU 80cm telescope
  59. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: DECam GW-MMADS candidates
  60. GRB 250225A: Fermi GBM Final Real-time Localization
  61. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: AstroSat CZTI non-detection and upper limits
  62. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Magellan upper limits.
  63. EP250223a: Kinder optical follow-up observations
  64. GRB 250207a: ATCA Radio Upper Limits
  65. LIGO/Virgo/KAGRA S250223dk: DECam DESGW Candidates
  66. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Upper limits from Fermi-GBM Observations
  67. GRB 250119B: VZLUSAT-2 detection
  68. GRB 250223C: Fermi GBM Final Real-time Localization
  69. GOTO observations of LVK S250223dk/Swift-BAT RAVEN alert
  70. GRB 250202B: VZLUSAT-2 detection
  71. GRB 250219A: EP-FXT afterglow detection
  72. EP250223a: GOTO optical afterglow detections
  73. GRB 250222A: SVOM/GRM observation of a burst
  74. EP250223a: COLIBRÍ/DDRAGO Detection of the Optical Counterpart and Slow Fading
  75. GRB 250210A: VZLUSAT-2 detection
  76. GRB 250206A: VZLUSAT-2 detection
  77. EP250223a: REM NIR upper limit
  78. EP250223a: TRT optical afterglow observation
  79. EP250223a: refined analysis of the EP-WXT and FXT observations
  80. EP250223a: 1.6m Mephisto and 50cm array observations
  81. GRB 250221A: TNOT detection of the optical counterpart
  82. EP250223a: SVOM/VT optical observation
  83. LIGO/Virgo/KAGRA S250223dk: DDOTI Upper Limits on the Optical Counterpart
  84. 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
  85. The EP-WXT trigger 01709131882 is likely a flaring star
  86. EP250223a: OASDG optical observations
  87. EP250223a: LCO detection of the afterglow
  88. EP250223a: early optical detection by BOOTES-4
  89. EP250223a: NOT redshift z = 2.756
  90. EP250223a: Swift/XRT localization
  91. EP250223a: NOT optical afterglow candidate
  92. GRB 250223B: Fermi GBM Final Localization
  93. EP250223a: Global MASTER-Net observations report
  94. GRB 250221A: VLA radio detection
  95. Fermi GRB 250223A: Global MASTER-Net observations report
  96. Fermi trigger No 762020305: Global MASTER-Net observations report
  97. GRB 250223A: Fermi GBM Final Real-time Localization
  98. EP250223a: Einstein Probe detection of an X-ray transient
  99. LIGO/Virgo/KAGRA S250206dm: Upper limits from IceCube neutrino searches
  100. GRB 250221A: continued Assy optical observations, brightening afterglow confirmation

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