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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"

12111 results found.

  1. GRB 240914B: AstroSat CZTI detection
  2. EP240913A / GRB 240913C: AstroSat CZTI detection
  3. EP240913a: Swift/XRT detection of an X-ray source within the EP/WXT error circle
  4. GRB 240914A : An intermediate duration GRB located on-board by SVOM/ECLAIRs.
  5. EP240913a: EP-WXT detection of a fast X-ray transient
  6. GRB 240913B: Fermi GBM Final Real-time Localization
  7. GRB 240912A: Swift-XRT refined Analysis
  8. GRB 240912A: NOT optical spectroscopy
  9. GRB 240912A: Swift detection of a burst with an optical counterpart
  10. GRB 240911A : a likely weak GRB detected by SVOM/ECLAIRs
  11. GRB 240825A: 7DT Optical Upper Limit
  12. LIGO/Virgo/KAGRA S240910ci: NED Galaxies in the Localization Volume
  13. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  14. EP240908a: Updates on the WXT detection result around the trigger time
  15. Fermi GRB 240910A: Global MASTER-Net observations report
  16. LIGO/Virgo/KAGRA S240908bs: Upper limits from Swift/BAT-GUANO
  17. LIGO/Virgo/KAGRA S240907cg: Upper limits from Swift/BAT-GUANO
  18. GRB 240905E: GIT optical upper limit
  19. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  20. GRB 240905B: Fermi-LAT detection
  21. GRB 240905E: SVOM/C-GFT optical upper limit
  22. GRB 240902B: AstroSat CZTI detection of a long burst
  23. GRB 240905E: Swift-XRT refined Analysis
  24. GRB 240902A: AstroSat CZTI detection of a long burst
  25. GRB 240905D: AstroSat CZTI detection
  26. GRB 240905B: AstroSat CZTI detection and localization
  27. LIGO/Virgo/KAGRA S240825ar: Upper limits from Swift/BAT-GUANO
  28. LIGO/Virgo/KAGRA S240807h: Upper limits from Swift/BAT-GUANO
  29. GRB 240825A: MeerLICHT afterglow detection
  30. Fermi trigger No 746923430: Global MASTER-Net observations report
  31. GRB 240828B: Mephisto optical upper limit
  32. LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
  33. GRB 240825A: MeerKAT detection
  34. GRB 240828B: J-band upper limit from WINTER
  35. GRB 240828B: GWAC-F50A optical upper limit
  36. GRB 240828B: SAO RAS optical upper limit
  37. Fermi trigger No 746587425: Global MASTER-Net observations report
  38. GRB 240828A: Swift-XRT afterglow detection
  39. GRB 240828A: Fermi-LAT detection
  40. LAT GRB240828.62: Global MASTER-Net observations report
  41. GRB 240828A: AstroSat CZTI detection of a long burst
  42. Fermi GRB 240828A: Bassano Bresciano Observatory upper limit
  43. GRB 240819A as a likely X-Ray Flash
  44. GRB 240821A: PRIME near-infrared observations
  45. Fermi trigger No 746438824: Global MASTER-Net observations report
  46. GRB 240825A: TNG optical photometry and spectroscopy
  47. Konus-Wind detection of GRB 240825A (bright/long)
  48. GRB 240825A: AstroSat CZTI detection of the long bright burst
  49. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  50. GRB 240825A: Swift/UVOT Detection
  51. GRB 240825A: Swift-XRT refined Analysis
  52. GRB 240825A: Fermi-LAT detection
  53. GRB 240825A: LCO optical observations
  54. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  55. Fermi GRB 240825A: Global MASTER-Net observations report
  56. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  57. GRB 240824B: MAXI/GSC detection
  58. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  59. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  60. GRB 240821A: Colibri Optical Upper Limit
  61. GRB 240822A: AstroSat CZTI detection of a short burst
  62. GECAM-B observation of a short burst from SGR 1E 1841-045 / Kes 73
  63. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  64. Fermi trigger No 745866488: Global MASTER-Net observations report
  65. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  66. GRB 240819A: Swift-XRT observations
  67. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  68. EP240820a: EP detection of a fast X-ray transient
  69. Trigger 1249653: Swift detection of SGR 1E 1841-045 / Kes 73
  70. Fermi trigger No 745873283: Global MASTER-Net observations report
  71. Fermi trigger No 745871958: Global MASTER-Net observations report
  72. Fermi Gamma-ray Burst Monitor trigger 745811685 / 240820080 is not a GRB
  73. GRB 240820A: Fermi GBM Final Real-time Localization
  74. Integral GRB240816.79: Global MASTER-Net observations report
  75. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  76. GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
  77. EP240816a: EP detection of a fast X-ray transient and follow-up observation
  78. EP240816b: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  79. Konus-Wind detection of GRB 240811A
  80. Konus-Wind detection of GRB 240810A
  81. IPN triangulation of GRB 240810A (short)
  82. GRB 240812B: AstroSat CZTI detection of a long burst
  83. GRB 240811A: Bassano Bresciano Observatory upper limit
  84. GRB 240811A: Swift-XRT refined Analysis
  85. EP240801a: Assy-Turgen optical observations
  86. GRB 240811A: LCOGT Optical Upper Limit
  87. Konus-Wind detection of GRB 240809A
  88. Fermi trigger No 745057312: Global MASTER-Net observations report
  89. Swift GRB 240811A: Global MASTER-Net observations report
  90. GRB 240811A: Swift detection of a burst
  91. GRB 240809A: Bassano Bresciano Observatory optical observations
  92. Konus-Wind detection of GRB 240807A (a counterpart of EP240807a)
  93. Fermi-LAT gamma-ray observations of IceCube-240808A
  94. GRB 240808A: AstroSat CZTI detection
  95. GRB 240809B: MAXI/GSC detection
  96. GRB 240809A: Swift detection of a burst with a bright optical counterpart
  97. EP240807a: STEP/T80S optical limits
  98. GRB 240807B: AstroSat CZTI detection of a short burst
  99. EP EP240807a: Global MASTER-Net observations report
  100. EP EP240806a: Global MASTER-Net observations report

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