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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"

43952 results found.

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

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