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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"

43117 results found.

  1. EP250302a: Montarrenti Observatory optical detection
  2. Fermi GRB 250302A: Global MASTER-Net observations report
  3. EP250302a: FTW optical and NIR detection
  4. EP250302a: Nanshan/HMT optical counterpart detection
  5. IceCube-250302A - IceCube observation of a high-energy neutrino candidate track-like event
  6. GRB 250302A: Fermi GBM Final Real-time Localization
  7. GRB 250228A: Fermi GBM Final Localization
  8. The EP-WXT trigger 01709132140 is likely a flaring star
  9. LIGO/Virgo/KAGRA S250206dm: early X-ray upper limits from Einstein Probe WXT and preliminary results of FXT observations
  10. GRB 250225B: VLT near-infrared afterglow confirmation
  11. EP250228a: Optical observations with Kinder and Swift/UVOT
  12. Konus-Wind detection of GRB 250226A
  13. GRB 250225B: EIRSAT-1 GMOD Detection
  14. GRB 250226A: KAO Optical Upper Limit
  15. GRB 250226A: AbAO AS-32 Optical Upper Limit
  16. EP250227a: Global MASTER-Net observations report
  17. EP250223A: Upper limits from Fermi-GBM Observations
  18. EP250227a: TRT optical upper limit
  19. GRB 250225B: VLT/HAWKI near-infrared observations
  20. EP250227a: Optical upper limits with Kinder observations
  21. EP250227a: NOT optical observations
  22. EP250227a: Einstein Probe detected of a fast X-ray transient
  23. EP250228a: updates on the EP observations
  24. GRB 250226A: Fermi GBM Observation
  25. EP250225a: EP-FXT follow-up observation
  26. EP250223a: J band upper limit by SYSU 80cm telescope
  27. EP250228a: Swift/XRT localisation
  28. EP250228a: Global MASTER-Net observations report
  29. EP250228a: Einstein Probe detection of an X-ray transient
  30. GRB 250226A / EP250226a: LCO detection of the afterglow
  31. LIGO/Virgo/KAGRA S250227e: Updated Sky localization
  32. LIGO/Virgo/KAGRA S250226dl: Updated Sky localization
  33. GRB 250225B: VLT/Xshooter imaging
  34. GRB 250205A / EP250205A: further radio observations with the VLA
  35. GRB 250226B: INTEGRAL SPI-ACS and PICsIT detection
  36. EP250226a/GRB 250226A: INTEGRAL SPI-ACS and PICsIT detection
  37. GRB 250225B: INTEGRAL SPI-ACS detection
  38. EP250225a: NOT optical candidate counterpart
  39. EP250226a/GRB 250226A:Xinglong optical follow-up observations
  40. EP250226a / GRB 250226A: SVOM/VT optical observations
  41. EP250226a/GRB 250226A: refined analysis of the EP-WXT and FXT observations
  42. EP250225a: TRT optical upper limits
  43. EP250226a/GRB 250226A: 1.6m Mephisto observations
  44. LIGO/Virgo/KAGRA S250206dm: Upper limits from SVOM/GRM Observations
  45. EP250226a/GRB 250226A: Kinder optical follow-up observations
  46. LIGO/Virgo/KAGRA S250223dk: Insight-HXMT/HE sub-threshold detection of a burst (HEB 250223501)
  47. LIGO/Virgo/KAGRA S250227y: Retraction of GW compact binary merger candidate
  48. LIGO/Virgo/KAGRA S250227e: Identification of a GW compact binary merger candidate
  49. Fermi GRB 250226B: Global MASTER-Net observations report
  50. LIGO/Virgo/KAGRA S250226dl: Identification of a GW compact binary merger candidate
  51. GRB 250226B: Fermi GBM Final Real-time Localization
  52. GRB 250225B: Fermi GBM Observation
  53. GRB 250221A: ATCA Detections and Upper Limits
  54. GRB 250225B: REM NIR upper limits
  55. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Updated Sky localization and Coincidence with External Event
  56. Konus-Wind detection of GRB 250225B
  57. LIGO/Virgo/KAGRA S250223dk: DECam optical detections of Swift X-ray sources
  58. GRB 250225B: VLT optical and near-infrared candidate counterpart
  59. GRB 250225B: VLT/FORS2 candidate optical afterglow
  60. GRB 250225B: SVOM/GRM observation of a long burst
  61. GRB 250226A: GECAM-B detection
  62. GRB 250221A: EP-FXT detection of the X-ray afterglow
  63. GRB 250214A: SVOM/GRM observation
  64. EP250226a/GRB 250226A: GSP detects optical counterpart
  65. EP250226a/GRB 250226A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  66. EP250226a / GRB 250226A: VLT/X-shooter redshift of z = 3.315
  67. EP250226a / GRB 250226A: TRT optical counterpart observation
  68. LIGO/Virgo S250223dk: Swift XRT observations, 7 X-ray sources
  69. EP250226a: Global MASTER-Net observations report
  70. Swift GRB 250225B: Global MASTER-Net observations report
  71. EP250226a/GRB 250226A: EP-WXT detection and FXT follow-up observation of an X-ray transient
  72. Fermi GRB 250226A: Global MASTER-Net observations report
  73. Fermi trigger No 762205158: Global MASTER-Net observations report
  74. GRB 250226A: Fermi GBM Final Real-time Localization
  75. EP250225a: Global MASTER-Net observations report
  76. EP250225a: GSP optical upper limit
  77. EP250223a: GMG Optical Observation
  78. EP250225a: Einstein Probe detected of a fast X-ray transient
  79. Fermi GRB 250225A: Global MASTER-Net observations report
  80. GRB 250225B: Swift detection of a burst
  81. EP250223a: GROWTH-India Telescope optical observations
  82. GRB 250223C: SVOM/GRM observation of a long burst
  83. EP250215A: J band upper limit by SYSU 80cm telescope
  84. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: DECam GW-MMADS candidates
  85. GRB 250225A: Fermi GBM Final Real-time Localization
  86. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: AstroSat CZTI non-detection and upper limits
  87. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Magellan upper limits.
  88. EP250223a: Kinder optical follow-up observations
  89. GRB 250207a: ATCA Radio Upper Limits
  90. LIGO/Virgo/KAGRA S250223dk: DECam DESGW Candidates
  91. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Upper limits from Fermi-GBM Observations
  92. GRB 250119B: VZLUSAT-2 detection
  93. GRB 250223C: Fermi GBM Final Real-time Localization
  94. GOTO observations of LVK S250223dk/Swift-BAT RAVEN alert
  95. GRB 250202B: VZLUSAT-2 detection
  96. GRB 250219A: EP-FXT afterglow detection
  97. EP250223a: GOTO optical afterglow detections
  98. GRB 250222A: SVOM/GRM observation of a burst
  99. EP250223a: COLIBRÍ/DDRAGO Detection of the Optical Counterpart and Slow Fading
  100. GRB 250210A: VZLUSAT-2 detection

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