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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').
Advanced Search

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"

45796 results found.

  1. EP250226a/GRB 250226A: INTEGRAL SPI-ACS and PICsIT detection
  2. GRB 250225B: INTEGRAL SPI-ACS detection
  3. EP250225a: NOT optical candidate counterpart
  4. EP250226a/GRB 250226A:Xinglong optical follow-up observations
  5. EP250226a / GRB 250226A: SVOM/VT optical observations
  6. EP250226a/GRB 250226A: refined analysis of the EP-WXT and FXT observations
  7. EP250225a: TRT optical upper limits
  8. EP250226a/GRB 250226A: 1.6m Mephisto observations
  9. LIGO/Virgo/KAGRA S250206dm: Upper limits from SVOM/GRM Observations
  10. EP250226a/GRB 250226A: Kinder optical follow-up observations
  11. LIGO/Virgo/KAGRA S250223dk: Insight-HXMT/HE sub-threshold detection of a burst (HEB 250223501)
  12. LIGO/Virgo/KAGRA S250227y: Retraction of GW compact binary merger candidate
  13. LIGO/Virgo/KAGRA S250227e: Identification of a GW compact binary merger candidate
  14. Fermi GRB 250226B: Global MASTER-Net observations report
  15. LIGO/Virgo/KAGRA S250226dl: Identification of a GW compact binary merger candidate
  16. GRB 250226B: Fermi GBM Final Real-time Localization
  17. GRB 250225B: Fermi GBM Observation
  18. GRB 250221A: ATCA Detections and Upper Limits
  19. GRB 250225B: REM NIR upper limits
  20. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Updated Sky localization and Coincidence with External Event
  21. Konus-Wind detection of GRB 250225B
  22. LIGO/Virgo/KAGRA S250223dk: DECam optical detections of Swift X-ray sources
  23. EP250223a: CrAO ZTSH optical observation
  24. GRB 250225B: VLT optical and near-infrared candidate counterpart
  25. GRB 250225B: VLT/FORS2 candidate optical afterglow
  26. GRB 250225B: SVOM/GRM observation of a long burst
  27. GRB 250226A: GECAM-B detection
  28. GRB 250221A: EP-FXT detection of the X-ray afterglow
  29. GRB 250214A: SVOM/GRM observation
  30. EP250226a/GRB 250226A: GSP detects optical counterpart
  31. EP250226a/GRB 250226A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  32. EP250226a / GRB 250226A: VLT/X-shooter redshift of z = 3.315
  33. EP250226a / GRB 250226A: TRT optical counterpart observation
  34. LIGO/Virgo S250223dk: Swift XRT observations, 7 X-ray sources
  35. EP250226a: Global MASTER-Net observations report
  36. Swift GRB 250225B: Global MASTER-Net observations report
  37. EP250226a/GRB 250226A: EP-WXT detection and FXT follow-up observation of an X-ray transient
  38. Fermi GRB 250226A: Global MASTER-Net observations report
  39. Fermi trigger No 762205158: Global MASTER-Net observations report
  40. GRB 250226A: Fermi GBM Final Real-time Localization
  41. EP250225a: Global MASTER-Net observations report
  42. EP250225a: GSP optical upper limit
  43. EP250223a: GMG Optical Observation
  44. EP250225a: Einstein Probe detected of a fast X-ray transient
  45. Fermi GRB 250225A: Global MASTER-Net observations report
  46. GRB 250225B: Swift detection of a burst
  47. EP250223a: GROWTH-India Telescope optical observations
  48. GRB 250221A: Swift-BAT refined analysis
  49. GRB 250223C: SVOM/GRM observation of a long burst
  50. EP250215A: J band upper limit by SYSU 80cm telescope
  51. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: DECam GW-MMADS candidates
  52. GRB 250225A: Fermi GBM Final Real-time Localization
  53. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: AstroSat CZTI non-detection and upper limits
  54. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Magellan upper limits.
  55. EP250223a: Kinder optical follow-up observations
  56. GRB 250207a: ATCA Radio Upper Limits
  57. LIGO/Virgo/KAGRA S250223dk: DECam DESGW Candidates
  58. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Upper limits from Fermi-GBM Observations
  59. GRB 250119B: VZLUSAT-2 detection
  60. GRB 250223C: Fermi GBM Final Real-time Localization
  61. GOTO observations of LVK S250223dk/Swift-BAT RAVEN alert
  62. GRB 250202B: VZLUSAT-2 detection
  63. GRB 250219A: EP-FXT afterglow detection
  64. EP250223a: GOTO optical afterglow detections
  65. GRB 250222A: SVOM/GRM observation of a burst
  66. EP250223a: COLIBRÍ/DDRAGO Detection of the Optical Counterpart and Slow Fading
  67. GRB 250210A: VZLUSAT-2 detection
  68. GRB 250206A: VZLUSAT-2 detection
  69. EP250223a: REM NIR upper limit
  70. EP250223a: TRT optical afterglow observation
  71. EP250223a: refined analysis of the EP-WXT and FXT observations
  72. EP250223a: 1.6m Mephisto and 50cm array observations
  73. GRB 250221A: TNOT detection of the optical counterpart
  74. EP250223a: SVOM/VT optical observation
  75. LIGO/Virgo/KAGRA S250223dk: DDOTI Upper Limits on the Optical Counterpart
  76. 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
  77. The EP-WXT trigger 01709131882 is likely a flaring star
  78. EP250223a: OASDG optical observations
  79. EP250223a: LCO detection of the afterglow
  80. EP250223a: early optical detection by BOOTES-4
  81. EP250223a: NOT redshift z = 2.756
  82. EP250223a: Swift/XRT localization
  83. EP250223a: NOT optical afterglow candidate
  84. GRB 250223B: Fermi GBM Final Localization
  85. EP250223a: Global MASTER-Net observations report
  86. GRB 250221A: VLA radio detection
  87. Fermi GRB 250223A: Global MASTER-Net observations report
  88. Fermi trigger No 762020305: Global MASTER-Net observations report
  89. GRB 250223A: Fermi GBM Final Real-time Localization
  90. EP250223a: Einstein Probe detection of an X-ray transient
  91. LIGO/Virgo/KAGRA S250206dm: Upper limits from IceCube neutrino searches
  92. GRB 250221A: continued Assy optical observations, brightening afterglow confirmation
  93. GRB 250221A: continued Mondy optical observations, brightening afterglow
  94. GRB 250221A: Optical counterpart detection by LCO.
  95. GRB 250221A: Mondy optical observations
  96. Konus-Wind detection of GRB 250221A
  97. GRB 250221A: Assy optical observations
  98. EP250220a: FTW optical and NIR observations and upper limits
  99. EP250220a: EP-FXT follow-up observations
  100. GRB 250219A: NUTTelA-TAO / BSTI Optical Limits

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