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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"

11404 results found.

  1. GRB 240912A: NOT optical spectroscopy
  2. GRB 240912A: Swift detection of a burst with an optical counterpart
  3. GRB 240911A : a likely weak GRB detected by SVOM/ECLAIRs
  4. GRB 240825A: 7DT Optical Upper Limit
  5. LIGO/Virgo/KAGRA S240910ci: NED Galaxies in the Localization Volume
  6. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  7. EP240908a: Updates on the WXT detection result around the trigger time
  8. Fermi GRB 240910A: Global MASTER-Net observations report
  9. LIGO/Virgo/KAGRA S240908bs: Upper limits from Swift/BAT-GUANO
  10. LIGO/Virgo/KAGRA S240907cg: Upper limits from Swift/BAT-GUANO
  11. GRB 240905E: GIT optical upper limit
  12. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  13. GRB 240905B: Fermi-LAT detection
  14. GRB 240905E: SVOM/C-GFT optical upper limit
  15. GRB 240902B: AstroSat CZTI detection of a long burst
  16. GRB 240905E: Swift-XRT refined Analysis
  17. GRB 240902A: AstroSat CZTI detection of a long burst
  18. GRB 240905D: AstroSat CZTI detection
  19. GRB 240905B: AstroSat CZTI detection and localization
  20. LIGO/Virgo/KAGRA S240825ar: Upper limits from Swift/BAT-GUANO
  21. LIGO/Virgo/KAGRA S240807h: Upper limits from Swift/BAT-GUANO
  22. GRB 240825A: MeerLICHT afterglow detection
  23. Fermi trigger No 746923430: Global MASTER-Net observations report
  24. GRB 240828B: Mephisto optical upper limit
  25. LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
  26. GRB 240825A: MeerKAT detection
  27. GRB 240828B: J-band upper limit from WINTER
  28. GRB 240828B: GWAC-F50A optical upper limit
  29. GRB 240828B: SAO RAS optical upper limit
  30. Fermi trigger No 746587425: Global MASTER-Net observations report
  31. GRB 240828A: Swift-XRT afterglow detection
  32. GRB 240828A: Fermi-LAT detection
  33. LAT GRB240828.62: Global MASTER-Net observations report
  34. GRB 240828A: AstroSat CZTI detection of a long burst
  35. Fermi GRB 240828A: Bassano Bresciano Observatory upper limit
  36. GRB 240819A as a likely X-Ray Flash
  37. GRB 240821A: PRIME near-infrared observations
  38. Fermi trigger No 746438824: Global MASTER-Net observations report
  39. GRB 240825A: TNG optical photometry and spectroscopy
  40. Konus-Wind detection of GRB 240825A (bright/long)
  41. GRB 240825A: AstroSat CZTI detection of the long bright burst
  42. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  43. GRB 240825A: Swift/UVOT Detection
  44. GRB 240825A: Swift-XRT refined Analysis
  45. GRB 240825A: Fermi-LAT detection
  46. GRB 240825A: LCO optical observations
  47. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  48. Fermi GRB 240825A: Global MASTER-Net observations report
  49. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  50. GRB 240824B: MAXI/GSC detection
  51. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  52. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  53. GRB 240821A: Colibri Optical Upper Limit
  54. GRB 240822A: AstroSat CZTI detection of a short burst
  55. GECAM-B observation of a short burst from SGR 1E 1841-045 / Kes 73
  56. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  57. Fermi trigger No 745866488: Global MASTER-Net observations report
  58. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  59. GRB 240819A: Swift-XRT observations
  60. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  61. EP240820a: EP detection of a fast X-ray transient
  62. Trigger 1249653: Swift detection of SGR 1E 1841-045 / Kes 73
  63. Fermi trigger No 745873283: Global MASTER-Net observations report
  64. Fermi trigger No 745871958: Global MASTER-Net observations report
  65. Fermi Gamma-ray Burst Monitor trigger 745811685 / 240820080 is not a GRB
  66. GRB 240820A: Fermi GBM Final Real-time Localization
  67. Integral GRB240816.79: Global MASTER-Net observations report
  68. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  69. GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
  70. EP240816a: EP detection of a fast X-ray transient and follow-up observation
  71. EP240816b: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  72. Konus-Wind detection of GRB 240811A
  73. Konus-Wind detection of GRB 240810A
  74. IPN triangulation of GRB 240810A (short)
  75. GRB 240812B: AstroSat CZTI detection of a long burst
  76. GRB 240811A: Bassano Bresciano Observatory upper limit
  77. GRB 240811A: Swift-XRT refined Analysis
  78. EP240801a: Assy-Turgen optical observations
  79. GRB 240811A: LCOGT Optical Upper Limit
  80. Konus-Wind detection of GRB 240809A
  81. Fermi trigger No 745057312: Global MASTER-Net observations report
  82. Swift GRB 240811A: Global MASTER-Net observations report
  83. GRB 240811A: Swift detection of a burst
  84. GRB 240809A: Bassano Bresciano Observatory optical observations
  85. Konus-Wind detection of GRB 240807A (a counterpart of EP240807a)
  86. Fermi-LAT gamma-ray observations of IceCube-240808A
  87. GRB 240808A: AstroSat CZTI detection
  88. GRB 240809B: MAXI/GSC detection
  89. GRB 240809A: Swift detection of a burst with a bright optical counterpart
  90. EP240807a: STEP/T80S optical limits
  91. GRB 240807B: AstroSat CZTI detection of a short burst
  92. EP EP240807a: Global MASTER-Net observations report
  93. EP EP240806a: Global MASTER-Net observations report
  94. EP240807a/GRB 240807A: EP-FXT detection of the X-ray emission
  95. GRB 240720B: VZLUSAT-2 detection
  96. Fermi trigger No 744629911: Global MASTER-Net observations report
  97. Konus-Wind detection of GRB 240802A (EP240802a)
  98. Konus-Wind detection of GRB 240805A
  99. GRB 240805B Bassano Bresciano Observatory upper limit
  100. GRB 240805B: AbAO, CrAO, and Terskol optical upper limits

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