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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"

43112 results found.

  1. GRB 250302A: Fermi GBM Final Real-time Localization
  2. GRB 250228A: Fermi GBM Final Localization
  3. The EP-WXT trigger 01709132140 is likely a flaring star
  4. LIGO/Virgo/KAGRA S250206dm: early X-ray upper limits from Einstein Probe WXT and preliminary results of FXT observations
  5. GRB 250225B: VLT near-infrared afterglow confirmation
  6. EP250228a: Optical observations with Kinder and Swift/UVOT
  7. Konus-Wind detection of GRB 250226A
  8. GRB 250225B: EIRSAT-1 GMOD Detection
  9. GRB 250226A: KAO Optical Upper Limit
  10. GRB 250226A: AbAO AS-32 Optical Upper Limit
  11. EP250227a: Global MASTER-Net observations report
  12. EP250223A: Upper limits from Fermi-GBM Observations
  13. EP250227a: TRT optical upper limit
  14. GRB 250225B: VLT/HAWKI near-infrared observations
  15. EP250227a: Optical upper limits with Kinder observations
  16. EP250227a: NOT optical observations
  17. EP250227a: Einstein Probe detected of a fast X-ray transient
  18. EP250228a: updates on the EP observations
  19. GRB 250226A: Fermi GBM Observation
  20. EP250225a: EP-FXT follow-up observation
  21. EP250223a: J band upper limit by SYSU 80cm telescope
  22. EP250228a: Swift/XRT localisation
  23. EP250228a: Global MASTER-Net observations report
  24. EP250228a: Einstein Probe detection of an X-ray transient
  25. GRB 250226A / EP250226a: LCO detection of the afterglow
  26. LIGO/Virgo/KAGRA S250227e: Updated Sky localization
  27. LIGO/Virgo/KAGRA S250226dl: Updated Sky localization
  28. GRB 250225B: VLT/Xshooter imaging
  29. GRB 250205A / EP250205A: further radio observations with the VLA
  30. GRB 250226B: INTEGRAL SPI-ACS and PICsIT detection
  31. EP250226a/GRB 250226A: INTEGRAL SPI-ACS and PICsIT detection
  32. GRB 250225B: INTEGRAL SPI-ACS detection
  33. EP250225a: NOT optical candidate counterpart
  34. EP250226a/GRB 250226A:Xinglong optical follow-up observations
  35. EP250226a / GRB 250226A: SVOM/VT optical observations
  36. EP250226a/GRB 250226A: refined analysis of the EP-WXT and FXT observations
  37. EP250225a: TRT optical upper limits
  38. EP250226a/GRB 250226A: 1.6m Mephisto observations
  39. LIGO/Virgo/KAGRA S250206dm: Upper limits from SVOM/GRM Observations
  40. EP250226a/GRB 250226A: Kinder optical follow-up observations
  41. LIGO/Virgo/KAGRA S250223dk: Insight-HXMT/HE sub-threshold detection of a burst (HEB 250223501)
  42. LIGO/Virgo/KAGRA S250227y: Retraction of GW compact binary merger candidate
  43. LIGO/Virgo/KAGRA S250227e: Identification of a GW compact binary merger candidate
  44. Fermi GRB 250226B: Global MASTER-Net observations report
  45. LIGO/Virgo/KAGRA S250226dl: Identification of a GW compact binary merger candidate
  46. GRB 250226B: Fermi GBM Final Real-time Localization
  47. GRB 250225B: Fermi GBM Observation
  48. GRB 250221A: ATCA Detections and Upper Limits
  49. GRB 250225B: REM NIR upper limits
  50. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Updated Sky localization and Coincidence with External Event
  51. Konus-Wind detection of GRB 250225B
  52. LIGO/Virgo/KAGRA S250223dk: DECam optical detections of Swift X-ray sources
  53. GRB 250225B: VLT optical and near-infrared candidate counterpart
  54. GRB 250225B: VLT/FORS2 candidate optical afterglow
  55. GRB 250225B: SVOM/GRM observation of a long burst
  56. GRB 250226A: GECAM-B detection
  57. GRB 250221A: EP-FXT detection of the X-ray afterglow
  58. GRB 250214A: SVOM/GRM observation
  59. EP250226a/GRB 250226A: GSP detects optical counterpart
  60. EP250226a/GRB 250226A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  61. EP250226a / GRB 250226A: VLT/X-shooter redshift of z = 3.315
  62. EP250226a / GRB 250226A: TRT optical counterpart observation
  63. LIGO/Virgo S250223dk: Swift XRT observations, 7 X-ray sources
  64. EP250226a: Global MASTER-Net observations report
  65. Swift GRB 250225B: Global MASTER-Net observations report
  66. EP250226a/GRB 250226A: EP-WXT detection and FXT follow-up observation of an X-ray transient
  67. Fermi GRB 250226A: Global MASTER-Net observations report
  68. Fermi trigger No 762205158: Global MASTER-Net observations report
  69. GRB 250226A: Fermi GBM Final Real-time Localization
  70. EP250225a: Global MASTER-Net observations report
  71. EP250225a: GSP optical upper limit
  72. EP250223a: GMG Optical Observation
  73. EP250225a: Einstein Probe detected of a fast X-ray transient
  74. Fermi GRB 250225A: Global MASTER-Net observations report
  75. GRB 250225B: Swift detection of a burst
  76. EP250223a: GROWTH-India Telescope optical observations
  77. GRB 250223C: SVOM/GRM observation of a long burst
  78. EP250215A: J band upper limit by SYSU 80cm telescope
  79. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: DECam GW-MMADS candidates
  80. GRB 250225A: Fermi GBM Final Real-time Localization
  81. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: AstroSat CZTI non-detection and upper limits
  82. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Magellan upper limits.
  83. EP250223a: Kinder optical follow-up observations
  84. GRB 250207a: ATCA Radio Upper Limits
  85. LIGO/Virgo/KAGRA S250223dk: DECam DESGW Candidates
  86. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Upper limits from Fermi-GBM Observations
  87. GRB 250119B: VZLUSAT-2 detection
  88. GRB 250223C: Fermi GBM Final Real-time Localization
  89. GOTO observations of LVK S250223dk/Swift-BAT RAVEN alert
  90. GRB 250202B: VZLUSAT-2 detection
  91. GRB 250219A: EP-FXT afterglow detection
  92. EP250223a: GOTO optical afterglow detections
  93. GRB 250222A: SVOM/GRM observation of a burst
  94. EP250223a: COLIBRÍ/DDRAGO Detection of the Optical Counterpart and Slow Fading
  95. GRB 250210A: VZLUSAT-2 detection
  96. GRB 250206A: VZLUSAT-2 detection
  97. EP250223a: REM NIR upper limit
  98. EP250223a: TRT optical afterglow observation
  99. EP250223a: refined analysis of the EP-WXT and FXT observations
  100. EP250223a: 1.6m Mephisto and 50cm array observations

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