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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"

2791 results found.

  1. Fermi trigger No 756678579: Global MASTER-Net observations report
  2. IceCube Alert 241224.30: Global MASTER-Net observations report
  3. GRB241113A: 7DT Optical upper limits
  4. GRB 241105A: JWST photometric observations of the host galaxy
  5. GRB 241223A: Fermi GBM Final Real-time Localization
  6. EP241217a : Leavitt Observatory optical upper limit
  7. EP241119a: 7DT Optical upper limits
  8. GRB 241213B: MAXI/GSC detection
  9. GRB 241209A: Chandra X-ray Detection
  10. Fermi GRB 241209E: Global MASTER-Net observations report
  11. Fermi GRB 241209A: Global MASTER-Net observations report
  12. GRB 241207C: MASTER optical observations
  13. Fermi trigger No 755225799: Global MASTER-Net observations report
  14. GRB 241207C: MAXI/GSC detection
  15. Fermi GRB 241207A: Global MASTER-Net observations report
  16. EP241206a: EP detection of a fast X-ray transient
  17. Fermi GRB 241204A: Global MASTER-Net observations report
  18. IceCube-241127A: No transient candidates from the Zwicky Transient Facility
  19. GRB 241130A: Fermi GBM Detection
  20. Fermi GRB 241201A: Global MASTER-Net observations report
  21. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  22. GRB 241128A: AbAO optical upper limit
  23. EP241126a: WFST Observations
  24. Swift GRB241127.91: Global MASTER-Net observations report
  25. Fermi GRB 241118A: Global MASTER-Net observations report
  26. GRB 241117A: Fermi GBM Detection
  27. EP241113a: Swift XRT weak detection
  28. EP241115a: EP detection of a fast X-ray transient
  29. EP 241113a: LBT possible optical counterpart
  30. GRB 241113B: KAIT Optical Afterglow Candidate
  31. EP241113a: Global MASTER-Net observations report
  32. LIGO/Virgo/KAGRA S241114y: Identification of a GW compact binary merger candidate
  33. Fermi trigger No 753166198: Global MASTER-Net observations report
  34. EP241107a: EP-FXT follow-up observations
  35. Fermi trigger No 752990530: Global MASTER-Net observations report
  36. Fermi trigger No 752878030: Global MASTER-Net observations report
  37. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  38. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  39. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  40. Fermi GRB 241105A: Global MASTER-Net observations report
  41. Fermi GRB 241104A: Global MASTER-Net observations report
  42. EP241101a: Optical upper limits with Kinder observations
  43. S241102cy: Identification of a GW compact binary merger candidate
  44. LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate
  45. GRB 241026A: SAO RAS optical observations
  46. Fermi trigger No 752006065: Global MASTER-Net observations report
  47. GRB 241030A: Keck/LRIS spectroscopic redshift z = 1.411
  48. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  49. GRB 241030A: Fermi GBM Final Real-time Localization
  50. GRB 241029A: Mephisto observations
  51. GRB 241026A: BTA and Zeiss-1000 optical observations
  52. EP241021a: further SAO RAS optical observations
  53. EP EP241026b: Global MASTER-Net observations report
  54. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  55. GRB 241025A: Fermi GBM Observation
  56. IPN triangulation of GRB 241022A (short/hard)
  57. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  58. GRB 241018A: EP-FXT afterglow detection
  59. GRB 240727A: VIRT Optical Upper Limit
  60. Fermi trigger No 750788395: Global MASTER-Net observations report
  61. Fermi GRB 241016A: Global MASTER-Net observations report
  62. Fermi trigger No 750211959: Global MASTER-Net observations report
  63. GRB 241010A: LCO optical observations
  64. Fermi GRB 241008A: Global MASTER-Net observations report
  65. IceCube-241006A: No candidates from the Zwicky Transient Facility
  66. IceCube Alert 241006.94: Global MASTER-Net observations report
  67. GRB 241006A: Swift detection of a burst
  68. EP trigger ID 01709065118: the X-ray transient is likely a stellar flare event
  69. Fermi trigger No 749693019: Global MASTER-Net observations report
  70. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  71. GRB 241002A: 1.5m OSN optical upper limit
  72. IceCube-240929A: Upper limits from a search for additional neutrino events in IceCube
  73. Fermi GRB 240930B: Global MASTER-Net observations report
  74. GRB 240930B: Fermi GBM Final Real-time Localization
  75. Fermi GRB 240930A: Global MASTER-Net observations report
  76. Fermi GRB 240929A: Global MASTER-Net observations report
  77. Konus-Wind detection of GRB 240912A
  78. LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
  79. EP trigger ID 01709059262: correction to the observation start time and source localization
  80. EP trigger ID 01709059262: the X-ray transient is likely a stellar flare event
  81. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  82. GRB 240919A / EP240919a: SVOM/GRM observation
  83. EP240919a: NOT and Gemini optical observations
  84. EP240919a is likely a GRB event
  85. EP240919a: EP-WXT detection of a fast X-ray transient
  86. EP240918b and EP240918c: EP-WXT detection of two fast X-ray transients
  87. EP EP240918a: Global MASTER-Net observations report
  88. GRB 240914B: AstroSat CZTI detection
  89. EP240913a: Swift/XRT detection of an X-ray source within the EP/WXT error circle
  90. GRB 240914B: BALROG localization (Fermi Trigger 747990592 / GRB 240914298)
  91. GRB 240912A: SVOM/GRM observation
  92. GRB 240825A: 7DT Optical Upper Limit
  93. GRB 240902B: AstroSat CZTI detection of a long burst
  94. GRB 240825A: Montarrenti Observatory optical follow-up observations
  95. Fermi trigger No 746923430: Global MASTER-Net observations report
  96. GRB 240828B: SVOM/C-GFT optical upper limit
  97. Fermi GRB 240828A: Bassano Bresciano Observatory upper limit
  98. Fermi trigger No 746438824: Global MASTER-Net observations report
  99. GRB 240828A: Fermi GBM Final Real-time Localization
  100. Swift GRB240824.04: Global MASTER-Net observations report

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