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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"

12109 results found.

  1. EP240913a: Swift/XRT detection of an X-ray source within the EP/WXT error circle
  2. GRB 240914A : An intermediate duration GRB located on-board by SVOM/ECLAIRs.
  3. EP240913a: EP-WXT detection of a fast X-ray transient
  4. GRB 240913B: Fermi GBM Final Real-time Localization
  5. GRB 240912A: Swift-XRT refined Analysis
  6. GRB 240912A: NOT optical spectroscopy
  7. GRB 240912A: Swift detection of a burst with an optical counterpart
  8. GRB 240911A : a likely weak GRB detected by SVOM/ECLAIRs
  9. GRB 240825A: 7DT Optical Upper Limit
  10. LIGO/Virgo/KAGRA S240910ci: NED Galaxies in the Localization Volume
  11. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  12. EP240908a: Updates on the WXT detection result around the trigger time
  13. Fermi GRB 240910A: Global MASTER-Net observations report
  14. LIGO/Virgo/KAGRA S240908bs: Upper limits from Swift/BAT-GUANO
  15. LIGO/Virgo/KAGRA S240907cg: Upper limits from Swift/BAT-GUANO
  16. GRB 240905E: GIT optical upper limit
  17. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  18. GRB 240905B: Fermi-LAT detection
  19. GRB 240905E: SVOM/C-GFT optical upper limit
  20. GRB 240902B: AstroSat CZTI detection of a long burst
  21. GRB 240905E: Swift-XRT refined Analysis
  22. GRB 240902A: AstroSat CZTI detection of a long burst
  23. GRB 240905D: AstroSat CZTI detection
  24. GRB 240905B: AstroSat CZTI detection and localization
  25. LIGO/Virgo/KAGRA S240825ar: Upper limits from Swift/BAT-GUANO
  26. LIGO/Virgo/KAGRA S240807h: Upper limits from Swift/BAT-GUANO
  27. GRB 240825A: MeerLICHT afterglow detection
  28. Fermi trigger No 746923430: Global MASTER-Net observations report
  29. GRB 240828B: Mephisto optical upper limit
  30. LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
  31. GRB 240825A: MeerKAT detection
  32. GRB 240828B: J-band upper limit from WINTER
  33. GRB 240828B: GWAC-F50A optical upper limit
  34. GRB 240828B: SAO RAS optical upper limit
  35. Fermi trigger No 746587425: Global MASTER-Net observations report
  36. GRB 240828A: Swift-XRT afterglow detection
  37. GRB 240828A: Fermi-LAT detection
  38. LAT GRB240828.62: Global MASTER-Net observations report
  39. GRB 240828A: AstroSat CZTI detection of a long burst
  40. Fermi GRB 240828A: Bassano Bresciano Observatory upper limit
  41. GRB 240819A as a likely X-Ray Flash
  42. GRB 240821A: PRIME near-infrared observations
  43. Fermi trigger No 746438824: Global MASTER-Net observations report
  44. GRB 240825A: TNG optical photometry and spectroscopy
  45. Konus-Wind detection of GRB 240825A (bright/long)
  46. GRB 240825A: AstroSat CZTI detection of the long bright burst
  47. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  48. GRB 240825A: Swift/UVOT Detection
  49. GRB 240825A: Swift-XRT refined Analysis
  50. GRB 240825A: Fermi-LAT detection
  51. GRB 240825A: LCO optical observations
  52. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  53. Fermi GRB 240825A: Global MASTER-Net observations report
  54. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  55. GRB 240824B: MAXI/GSC detection
  56. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  57. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  58. GRB 240821A: Colibri Optical Upper Limit
  59. GRB 240822A: AstroSat CZTI detection of a short burst
  60. GECAM-B observation of a short burst from SGR 1E 1841-045 / Kes 73
  61. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  62. Fermi trigger No 745866488: Global MASTER-Net observations report
  63. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  64. GRB 240819A: Swift-XRT observations
  65. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  66. EP240820a: EP detection of a fast X-ray transient
  67. Trigger 1249653: Swift detection of SGR 1E 1841-045 / Kes 73
  68. Fermi trigger No 745873283: Global MASTER-Net observations report
  69. Fermi trigger No 745871958: Global MASTER-Net observations report
  70. Fermi Gamma-ray Burst Monitor trigger 745811685 / 240820080 is not a GRB
  71. GRB 240820A: Fermi GBM Final Real-time Localization
  72. Integral GRB240816.79: Global MASTER-Net observations report
  73. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  74. GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
  75. EP240816a: EP detection of a fast X-ray transient and follow-up observation
  76. EP240816b: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  77. Konus-Wind detection of GRB 240811A
  78. Konus-Wind detection of GRB 240810A
  79. IPN triangulation of GRB 240810A (short)
  80. GRB 240812B: AstroSat CZTI detection of a long burst
  81. GRB 240811A: Bassano Bresciano Observatory upper limit
  82. GRB 240811A: Swift-XRT refined Analysis
  83. EP240801a: Assy-Turgen optical observations
  84. GRB 240811A: LCOGT Optical Upper Limit
  85. Konus-Wind detection of GRB 240809A
  86. Fermi trigger No 745057312: Global MASTER-Net observations report
  87. Swift GRB 240811A: Global MASTER-Net observations report
  88. GRB 240811A: Swift detection of a burst
  89. GRB 240809A: Bassano Bresciano Observatory optical observations
  90. Konus-Wind detection of GRB 240807A (a counterpart of EP240807a)
  91. Fermi-LAT gamma-ray observations of IceCube-240808A
  92. GRB 240808A: AstroSat CZTI detection
  93. GRB 240809B: MAXI/GSC detection
  94. GRB 240809A: Swift detection of a burst with a bright optical counterpart
  95. EP240807a: STEP/T80S optical limits
  96. GRB 240807B: AstroSat CZTI detection of a short burst
  97. EP EP240807a: Global MASTER-Net observations report
  98. EP EP240806a: Global MASTER-Net observations report
  99. EP240807a/GRB 240807A: EP-FXT detection of the X-ray emission
  100. GRB 240720B: VZLUSAT-2 detection

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