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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

11622 results found.

  1. GRB 250717B: Fermi GBM Observation
  2. GRB 250717B: Swift/BAT-GUANO arcminute localization of a burst
  3. Konus-Wind detection of GRB 250716A
  4. GRB 250716A: Swift-XRT afterglow detection
  5. GRB 250717B: Fermi GBM Final Real-time Localization
  6. GRB 250716A: Lesedi Detection of Fading Optical Transient GOTO25eyp
  7. GRB 250717A: Fermi GBM Final Real-time Localization
  8. GRB 250716A: Swift ToO observations
  9. GRB 250716A: GOTO tentative optical counterpart candidate
  10. GRB 250716A: Fermi GBM Observation
  11. GRB 250714A: SVOM/GRM observation
  12. Fermi GRB 250716A: Global MASTER-Net observations report
  13. GRB 250716A: Fermi GBM Final Real-time Localization
  14. Fermi GRB 250715A: Global MASTER-Net observations report
  15. GRB 250715A: Fermi GBM Final Real-time Localization
  16. EP250702a / GRB 250702B,D,E: Hubble Space Telescope Observations
  17. Fermi GRB 250714A: Global MASTER-Net observations report
  18. GRB 250714A: Fermi GBM Final Real-time Localization
  19. GRB 250711A: DDOTI Optical Upper Limit
  20. GRB 250711A: SVOM/GRM observation
  21. Fermi GRB 250711A: Global MASTER-Net observations report
  22. GRB 250711A: BALROG localization (Fermi Trigger 773937617 / GRB 250711611)
  23. GRB 250711A: Fermi GBM Final Real-time Localization
  24. GRB 250702B,D,E / EP250702a: ALMA detection
  25. GRB 250702B,D,E / EP250702a: 10 GHz detection with the VLA
  26. GRB 250709A: Fermi GBM Final Localization
  27. GRB 250706B/C: Insight-HXMT detection
  28. GRB250702 B,D,E / EP250702a: MOSFIRE imaging of the afterglow
  29. IPN triangulation of GRB 250706C (consistent with the GRB 250706B)
  30. IceCube-250708A - IceCube observation of a high-energy neutrino candidate track-like event
  31. Fermi GRB 250708A: Global MASTER-Net observations report
  32. GRB 250708A: Fermi GBM Final Real-time Localization
  33. GRB 250706B/C: Konus-Wind analysis of the prompt emission
  34. GRB 250706B: SVOM observations interpreted as the afterglow of GRB 250706C
  35. GRB 250702F: radio detection with the VLA
  36. GRB 250706B/C: VLT/X-shooter redshift z = 0.942
  37. Fermi-LAT Gamma-ray Observations of IceCube-250706A
  38. GRB 250706B/C: Fermi-LAT detection
  39. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  40. GRB 250702F: GRANDMA observations
  41. IceCube-250706A - IceCube observation of a high-energy neutrino candidate track-like event
  42. GRBs 250702B,C,D,E / EP250702a: J band upper limit by SYSU 80cm infrared telescope
  43. GRB 250703A: EIRSAT-1 GMOD Detection
  44. EP250702a/GRB 250702B,C,D,E: Archival radio observations from ASKAP VAST
  45. Konus-Wind detection of GRB 250703A
  46. IPN triangulation of GRB 250703A
  47. GRB 250702F: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  48. GRB 250702F: Kilonova-Catcher optical afterglow detection
  49. GRB250702F: afterglow detected by joint EP-ZTF shadowing program
  50. GRBs 250702B,D,E / EP250702a: fast fading, extremely red counterpart
  51. LIGO/Virgo/KAGRA S250704ab: Upper limits from Fermi-GBM Observations
  52. GRB 250702A: Insight-HXMT detection
  53. GRBs 250702B/C/D/E / EP250702a: Swift/UVOT Upper Limits
  54. GRB 250702B / EP2050702a: FTW optical and NIR observations
  55. Konus-Wind detection of GRB 250702F
  56. GRB 250702F: GROWTH-India Telescope optical observations
  57. EP250702a: WFST optical observations
  58. GRB 250702F: optical photometry from Konkoly
  59. GRB 250702F: SVOM/VT optical observation
  60. GRB 250702A: CALET Gamma-Ray Burst Monitor detection
  61. Fermi GBM Analysis of GRB 250702B (formerly B,D,E); dissociation of C burst
  62. Fermi GRB 250703A: Global MASTER-Net observations report
  63. GRBs 250702B,C,D,E / EP250702a: 2.2m CAHA optical upper limit
  64. GRB 250702F: Fermi GBM Observation
  65. GRB 250702F: Leavitt Observatory optical observations
  66. GRB 250702F: AKO Optical Afterglow Detection
  67. GRBs 250702B,C,D,E / EP250702a: VLT/HAWK-I NIR candidate
  68. GRBs 250702B,C,D,E / EP250702a: SVOM/GRM observation
  69. GRB 250702A: GECAM-B detection
  70. GRBs 250702B/C/D/E / EP250702a: Swift XRT localization
  71. GRB 250702B,C,D,E/EP250702a: COLIBRÍ optical upper limit
  72. EP250702a/GRB 250702B, C, D, E: EP-FXT follow-up observation
  73. GRB 250702F: TRT Optical Observation
  74. GRB 250703A: DDOTI Optical Upper Limit
  75. GRBs 250702B,C,D,E / EP250702a: Konus-Wind detection of a hard X-ray transient activity
  76. GRB 250702F: REM optical afterglow detection
  77. GRB 250702F: DDOTI Optical Observation
  78. GRB 250702B,C,D,E / EP 250702a: MAXI/GSC detection
  79. GRB 250703A: Fermi GBM Final Real-time Localization
  80. EP250702a/GRB 250702B,C,D,E: GOTO optical upper limits
  81. EP250702a : an X-ray transient detected by Einstein Probe likely associated with GRB 250702B,C,D,E
  82. Fermi GRB 250702E: Global MASTER-Net observations report
  83. Fermi GRB 250702B: Global MASTER-Net observations report
  84. GRB 250702D, C, E: Swift/BAT-GUANO localization skymap of a burst or galactic transient
  85. GRB 250702F: GTC/OSIRIS+ spectroscopic redshift z = 1.520
  86. GRB 250702F: NOT observations of the optical afterglow
  87. GRB 250702F: MASTER optical afterglow observation
  88. Fermi GRB 250702F: Global MASTER-Net observations report
  89. Fermi GRB 250702C: Global MASTER-Net observations report
  90. GRB 250702F: GOTO optical counterpart detection
  91. GRB 250702F: Ondrejov D50 optical afterglow detection
  92. GRB 250702F: Swift detection of a burst with an optical counterpart
  93. GRB 250702F: Fermi GBM Final Real-time Localization
  94. Fermi GBM Triggers 250702B, C, D and E are likely from the same source
  95. GRB 250702E: Fermi GBM Final Real-time Localization
  96. GRB 250702A: Fermi GBM Detection
  97. GRB 250702D: Fermi GBM Final Localization Correction
  98. GRB 250702C: Fermi GBM Final Real-time Localization
  99. GRB 250702B: Fermi GBM Final Real-time Localization
  100. GRB 250702A: BALROG localization (Fermi Trigger 773142852 / GRB 250702413)

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