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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

512 results found.

  1. GRB 260925A: Swift/UVOT Upper Limits
  2. Konus-Wind detection of GRB 260922A
  3. GRB 260924A: Fermi GRB Observation
  4. GRB 260924A: Fermi-LAT detection of a bright burst
  5. ATCA observations of GRB 260909A
  6. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  7. GRB 260829A: AstroSat CZTI detection
  8. GRB 260825A: SVOM/GRM observation of a long burst
  9. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  10. SN 2026stf / GRB 260708A: ATLAS forced photometry
  11. GRB 260708A: Fermi-GBM observation
  12. GRB 260616A: SVOM/GRM observation
  13. Konus-Wind detection of GRB 260616B/EP260616a
  14. GRB 260610B: Fermi GBM Observation
  15. Konus-Wind detection of GRB 260607B
  16. SVOM GRB260604.85: Global MASTER-Net observations report
  17. GRB 260601B/EP260601a: SVOM/VT optical observations
  18. AT 2026nuz: COLIBRÍ optical observations
  19. EP260527a: COLIBRÍ optical detection
  20. Fermi GRB 260525A: Global MASTER-Net observations report
  21. Fermi GRB 260516B: Global MASTER-Net observations report
  22. EP260514a: Global MASTER-Net observations report
  23. EP260512a: Global MASTER-Net observations report
  24. Fermi trigger No 797912738: Global MASTER-Net observations report
  25. Fermi GRB 260318A: Global MASTER-Net observations report
  26. GRB 260308A: SVOM/GRM observation of a short GRB
  27. EP260227a: Thai National Telescope observations
  28. GRB 260225D: Glowbug gamma-ray detection of a likely short burst
  29. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  30. EP260214a: Optical upper limits with Kinder observations
  31. GRB 260210A: SVOM/GRM observation
  32. GRB 260206A: Swift-XRT observations
  33. GRB 260206A (or XRB from 4U 0513-40): MAXI/GSC detection
  34. GRB 260204A : MASTER Global robotic net optical observations
  35. EP260126a: Seimei/TriCCS optical upper limit
  36. GRB 260120A: AstroSat CZTI detection
  37. GRB 260120B: SVOM/GRM observation
  38. EP260110a: Global MASTER-Net observations report
  39. SVOM GRB251203B: Global MASTER-Net observations report
  40. GRB 251128A: AstroSat CZTI detection
  41. Fermi GRB 251125B: Global MASTER-Net observations report
  42. Fermi GRB 251124a: Global MASTER-Net observations report
  43. IPN triangulation of GRB 251105B (possible sGRB with EE)
  44. GRB 251103B: Swift-XRT refined Analysis
  45. GRB 251011A: Fermi GBM Observation
  46. GRB 251011A: AstroSat CZTI detection
  47. Swift GRB 251001B: Global MASTER-Net observations report
  48. Konus-Wind detection of GRB 250919A
  49. EP250911a: Swift-XRT observations
  50. EP250908c: refined analysis of the EP-WXT and EP-FXT observations
  51. SVOM/sb25090605: detection of an X-ray transient from the LMXB 4U 0513-40
  52. GRB 250821B: AstroSat CZTI detection
  53. LIGO/Virgo/KAGRA S250818k: Updated Sky localization and EM Bright Classification
  54. sb25081602: Swift-XRT observations
  55. SVOM/sb25081602: detection of a likely X-ray transient
  56. EP250802a: Global MASTER-Net observations report
  57. The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
  58. Konus-Wind detection of GRB 250601A
  59. Swift GRB250603.05: Global MASTER-Net observations report
  60. The EP-WXT trigger 01709135179: Kinder optical counterpart candidate
  61. Fermi trigger No 766173972: Global MASTER-Net observations report
  62. EP250402a: Optical upper limit with Kinder observations
  63. GRB 250403A: SVOM/C-GFT optical observations
  64. GRB 250331D: Swift-XRT observations
  65. EP-WXT trigger 01709133021: Optical upper limit through Kinder observations
  66. GRB 250317C: AstroSat CZTI detection
  67. Fermi GRB 250226A: Global MASTER-Net observations report
  68. GRB 250217C: Fermi GBM Observation
  69. GRB 250211A: SVOM trigger sb25021103 is not a GRB
  70. GRB 250206A: Swift-XRT observations
  71. LIGO/Virgo/KAGRA S250206dm: Identification of a GW compact binary merger candidate
  72. Konus-Wind detection of GRB 250117A
  73. Konus-Wind detection of GRB 241204A (short/hard)
  74. GRB 241209D: AstroSat CZTI detection
  75. GRB 241201A: AstroSat CZTI detection
  76. GRB 241117A: Fermi GBM Detection
  77. Fermi trigger No 752878030: Global MASTER-Net observations report
  78. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  79. GRB 241104A: Fermi GBM Observation
  80. Fermi GRB 241104A: Global MASTER-Net observations report
  81. GRB 240912A: radio detection with the VLA
  82. Fermi trigger No 751861204: Global MASTER-Net observations report
  83. Fermi trigger No 750211959: Global MASTER-Net observations report
  84. EP240913A / GRB 240913C: AstroSat CZTI detection
  85. Fermi trigger No 746587425: Global MASTER-Net observations report
  86. LAT GRB240828.62: Global MASTER-Net observations report
  87. GRB 240801B: AstroSat CZTI detection of a bright long burst
  88. Konus-Wind detection of GRB 240718A
  89. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  90. Fermi trigger No 741211696: Global MASTER-Net observations report
  91. Fermi trigger No 739632045: Global MASTER-Net observations report
  92. Konus-Wind detection of GRB 240606B
  93. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
  94. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  95. MAXI GRB240514.78: Global MASTER-Net observations report
  96. GRB 240502C: GOTO possible optical counterpart candidates
  97. Fermi GRB 240502A: Global MASTER-Net observations report
  98. GRB240430A: Fermi GBM Final Localization
  99. IceCube Alert 240424.08: Global MASTER-Net observations report
  100. Swift Trigger 1220736: detection of 4U 1543-62.

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