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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').
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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

474 results found.

  1. SVOM GRB251203B: Global MASTER-Net observations report
  2. GRB 251128A: AstroSat CZTI detection
  3. Fermi GRB 251125B: Global MASTER-Net observations report
  4. Fermi GRB 251124a: Global MASTER-Net observations report
  5. IPN triangulation of GRB 251105B (possible sGRB with EE)
  6. GRB 251103B: Swift-XRT refined Analysis
  7. GRB 251011A: Fermi GBM Observation
  8. GRB 251011A: AstroSat CZTI detection
  9. Swift GRB 251001B: Global MASTER-Net observations report
  10. Konus-Wind detection of GRB 250919A
  11. EP250911a: Swift-XRT observations
  12. EP250908c: refined analysis of the EP-WXT and EP-FXT observations
  13. SVOM/sb25090605: detection of an X-ray transient from the LMXB 4U 0513-40
  14. GRB 250821B: AstroSat CZTI detection
  15. LIGO/Virgo/KAGRA S250818k: Updated Sky localization and EM Bright Classification
  16. sb25081602: Swift-XRT observations
  17. SVOM/sb25081602: detection of a likely X-ray transient
  18. EP250802a: Global MASTER-Net observations report
  19. The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
  20. Konus-Wind detection of GRB 250601A
  21. Swift GRB250603.05: Global MASTER-Net observations report
  22. The EP-WXT trigger 01709135179: Kinder optical counterpart candidate
  23. Fermi trigger No 766173972: Global MASTER-Net observations report
  24. EP250402a: Optical upper limit with Kinder observations
  25. GRB 250403A: SVOM/C-GFT optical observations
  26. GRB 250331D: Swift-XRT observations
  27. EP-WXT trigger 01709133021: Optical upper limit through Kinder observations
  28. GRB 250317C: AstroSat CZTI detection
  29. Fermi GRB 250226A: Global MASTER-Net observations report
  30. GRB 250217C: Fermi GBM Observation
  31. GRB 250211A: SVOM trigger sb25021103 is not a GRB
  32. GRB 250206A: Swift-XRT observations
  33. LIGO/Virgo/KAGRA S250206dm: Identification of a GW compact binary merger candidate
  34. Konus-Wind detection of GRB 250117A
  35. Konus-Wind detection of GRB 241204A (short/hard)
  36. GRB 241209D: AstroSat CZTI detection
  37. GRB 241201A: AstroSat CZTI detection
  38. GRB 241117A: Fermi GBM Detection
  39. Fermi trigger No 752878030: Global MASTER-Net observations report
  40. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  41. GRB 241104A: Fermi GBM Observation
  42. Fermi GRB 241104A: Global MASTER-Net observations report
  43. GRB 240912A: radio detection with the VLA
  44. Fermi trigger No 751861204: Global MASTER-Net observations report
  45. Fermi trigger No 750211959: Global MASTER-Net observations report
  46. EP240913A / GRB 240913C: AstroSat CZTI detection
  47. Fermi trigger No 746587425: Global MASTER-Net observations report
  48. LAT GRB240828.62: Global MASTER-Net observations report
  49. GRB 240801B: AstroSat CZTI detection of a bright long burst
  50. Konus-Wind detection of GRB 240718A
  51. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  52. Fermi trigger No 741211696: Global MASTER-Net observations report
  53. Fermi trigger No 739632045: Global MASTER-Net observations report
  54. Konus-Wind detection of GRB 240606B
  55. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
  56. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  57. MAXI GRB240514.78: Global MASTER-Net observations report
  58. GRB 240502C: GOTO possible optical counterpart candidates
  59. Fermi GRB 240502A: Global MASTER-Net observations report
  60. GRB240430A: Fermi GBM Final Localization
  61. IceCube Alert 240424.08: Global MASTER-Net observations report
  62. Swift Trigger 1220736: detection of 4U 1543-62.
  63. GRB 240403A: Fermi GBM Detection
  64. Fermi trigger No 733097506: Global MASTER-Net observations report
  65. GRB 231215A: further radio observations with the VLA
  66. Konus-Wind detection of GRB 240205B (long / very soft)
  67. IPN triangulation of GRB 240119A (short)
  68. Swift GRB240109.17: Global MASTER-Net observations report
  69. Fermi trigger No 724698747: Global MASTER-Net observations report
  70. IPN triangulation of GRB 231205A
  71. Fermi GRB 231103A: Global MASTER-Net observations report
  72. GRB 231104A: Swift-XRT refined Analysis
  73. GRB 230808A: Fermi GBM Detection
  74. LIGO/Virgo/KAGRA S230802aq: Updated Sky localization and EM Bright Classification
  75. Fermi trigger No 712713532: Global MASTER-Net observations report
  76. LIGO/Virgo/KAGRA S230802aq: Coverage and upper limits from MAXI/GSC observations
  77. LIGO/Virgo/KAGRA S230529ay: Updated Sky localization and EM Bright Classification
  78. LIGO/Virgo S230621bq: Global MASTER-Net observations report
  79. LIGO/Virgo S230621ad: Global MASTER-Net observations report
  80. Fermi GBM-230619: AstroSat CZTI non-detection and upper limits for the sub-threshold candidate
  81. LIGO/Virgo S230620al: Global MASTER-Net observations report
  82. LIGO/Virgo S230620g: Global MASTER-Net observations report
  83. LIGO/Virgo S230604z: Global MASTER-Net observations report
  84. LIGO/Virgo/KAGRA S230529ay: Identification of a GW compact binary merger candidate
  85. IceCube Alert 230524.47: Global MASTER-Net observations report
  86. Fermi trigger No 705503315: Global MASTER-Net observations report
  87. GRB 230307A: JWST second-epoch observations
  88. Trigger 1160641: Swift detection of 4U 1630-472 (a.k.a. SWIFT J1633.8-4724A)
  89. TESS Detection of the Optical Afterglow of GRB230307A
  90. Konus-Wind detection of GRB 230307A
  91. GRB 221120A: Fermi GBM observation
  92. GRB 221120A: GIT upper limits on optical afterglow
  93. GRB 221025A: AstroSat CZTI detection
  94. Fermi trigger No 687345829: Global MASTER-Net observations report
  95. Fermi trigger No 687344475: Global MASTER-Net observations report
  96. Integral GRB221013.04: Global MASTER-Net observations report
  97. Fermi trigger No 687014224: Global MASTER-Net observations report
  98. Fermi trigger No 681998863: Global MASTER-Net observations report
  99. Fermi GRB 220610A: Global MASTER-Net observations report
  100. Konus-Wind detection of GRB 220601A

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