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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"

42533 results found.

  1. GRB 250704B: SVOM/GRM observation of a short burst
  2. GRB 250702F: optical photometry from Konkoly
  3. GRB 250704A: REM detection of the optical afterglow
  4. LIGO/Virgo/KAGRA S250704ab: Coverage and upper limits from MAXI/GSC observations
  5. GRB 250702F: SVOM/VT optical observation
  6. LIGO/Virgo/KAGRA S250704ab: Identification of a GW compact binary merger candidate
  7. GRB 250704A: SVOM detection of a burst
  8. GRB 250702F: Swift/UVOT Detection
  9. Fermi GBM Analysis of GRB 250702B (formerly B,D,E); dissociation of C burst
  10. Fermi GRB 250703A: Global MASTER-Net observations report
  11. GRBs 250702B,C,D,E / EP250702a: 2.2m CAHA optical upper limit
  12. GRB 250702F: Swift-XRT refined Analysis
  13. GRB 250702F: Fermi GBM Observation
  14. GRB 250702F: Leavitt Observatory optical observations
  15. GRB 250702F: AKO Optical Afterglow Detection
  16. GRBs 250702B,C,D,E / EP250702a: VLT/HAWK-I NIR candidate
  17. GRBs 250702B,C,D,E / EP250702a: SVOM/GRM observation
  18. GRB 250702A: GECAM-B detection
  19. GRB 250702F: Skynet Optical Observations
  20. GRB 250424A: VIRT Optical Upper Limit
  21. GRBs 250702B/C/D/E / EP250702a: Swift XRT localization
  22. GRB 250702B,C,D,E/EP250702a: COLIBRÍ optical upper limit
  23. EP250702a/GRB 250702B, C, D, E: EP-FXT follow-up observation
  24. GRB 250702F: TRT Optical Observation
  25. GRB 250703A: DDOTI Optical Upper Limit
  26. GRBs 250702B,C,D,E / EP250702a: Konus-Wind detection of a hard X-ray transient activity
  27. GRB 250702F: REM optical afterglow detection
  28. EP250702a: Global MASTER-Net observations report
  29. GRB 250702F: DDOTI Optical Observation
  30. GRB 250702B,C,D,E / EP 250702a: MAXI/GSC detection
  31. GRB 250703A: Fermi GBM Final Real-time Localization
  32. EP250702a/GRB 250702B,C,D,E: GOTO optical upper limits
  33. GRB 250702F: COLIBRÍ Observations of the Afterglow
  34. EP250702a : an X-ray transient detected by Einstein Probe likely associated with GRB 250702B,C,D,E
  35. Fermi GRB 250702E: Global MASTER-Net observations report
  36. Fermi GRB 250702B: Global MASTER-Net observations report
  37. GRB 250702D, C, E: Swift/BAT-GUANO localization skymap of a burst or galactic transient
  38. GRB 250702F: Enhanced Swift-XRT position
  39. GRB 250702F: GTC/OSIRIS+ spectroscopic redshift z = 1.520
  40. GRB 250702F: NOT observations of the optical afterglow
  41. GRB 250702F: MASTER optical afterglow observation
  42. Fermi GRB 250702F: Global MASTER-Net observations report
  43. Fermi GRB 250702C: Global MASTER-Net observations report
  44. GRB 250702F: GOTO optical counterpart detection
  45. GRB 250702F: Ondrejov D50 optical afterglow detection
  46. GRB 250702F: Swift detection of a burst with an optical counterpart
  47. Swift GRB 250702F: Global MASTER-Net observations report
  48. GRB 250702F: Fermi GBM Final Real-time Localization
  49. Fermi GBM Triggers 250702B, C, D and E are likely from the same source
  50. GRB 250702E: Fermi GBM Final Real-time Localization
  51. Konus-Wind detection of GRB 250627A
  52. GRB 250702A: Fermi GBM Detection
  53. GRB 250702D: Fermi GBM Final Localization Correction
  54. GRB 250702C: Fermi GBM Final Real-time Localization
  55. LIGO/Virgo/KAGRA S250702n: Identification of a GW compact binary merger candidate
  56. GRB 250702B: Fermi GBM Final Real-time Localization
  57. GRB 250702A: BALROG localization (Fermi Trigger 773142852 / GRB 250702413)
  58. GRB 250702A: Fermi GBM Final Real-time Localization
  59. LIGO/Virgo/KAGRA S250701bq: Identification of a GW compact binary merger candidate
  60. LIGO/Virgo/KAGRA S250701bp: Identification of a GW compact binary merger candidate
  61. GRB 250628B: Swift-XRT observations
  62. GRB 250628B: SVOM/VT optical upper limit
  63. GRB 250628B: EP-FXT counterpart detection
  64. GRB 250627A: Insight-HXMT detection
  65. GRB 250627A: SVOM/GRM detection of a short burst
  66. LIGO/Virgo/KAGRA S250629bs: Identification of a GW compact binary merger candidate
  67. LIGO/Virgo/KAGRA S250629ae: Identification of a GW compact binary merger candidate
  68. GRB 250628A: REM optical/NIR upper limits
  69. GRB 250628C: Fermi GBM Final Real-time Localization
  70. LIGO/Virgo/KAGRA S250628am: Identification of a GW compact binary merger candidate
  71. GRB 250628B: SVOM detection of a long burst
  72. GRB 250625A: VLT/X-shooter spectroscopic observations at the afterglow position
  73. GRB 250628A: VLT/X-shooter upper limits
  74. GRB 250628A: Swift/UVOT Upper Limits
  75. GRB 250628A: Swift-XRT refined Analysis
  76. Fermi GRB 250626A: Global MASTER-Net observations report
  77. Swift GRB 250628A: Global MASTER-Net observations report
  78. GRB 250628A: Enhanced Swift-XRT position
  79. GRB 250628A: Swift detection of a burst
  80. GRB 250625A: Swift-BAT refined analysis
  81. GRB 250625A: Leavitt Observatory afterglow detection
  82. GRB 250625A: AbAO and INASAN Kislovodsk Optical Observations
  83. The EP-WXT trigger 01709179435 is likely a new outburst of the CV SS Cyg
  84. GRB 250625A: GTC/OSIRIS+ spectroscopic observations of the potential host galaxy
  85. GRB 250626A: Fermi GBM Final Real-time Localization
  86. GRB 250625A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  87. GRB 250625A: SVOM/C-GFT upper limit in early phase
  88. GRB 250625A: GECAM-B detection
  89. GRB 250625A: Swift/UVOT Upper Limits
  90. GRB 250625A: ABObservatory afterglow detection
  91. GRB 250625A: OHP/T193 optical detection
  92. GRB 250625A: COLIBRÍ optical observations
  93. GRB 250625A: Fermi-LAT detection
  94. GRB 250625A: Swift-XRT refined Analysis
  95. GRB 250625A: JinShan optical observations
  96. GRB250625A: Fermi GBM Observation
  97. Swift GRB 250625A: Global MASTER-Net observations report
  98. GRB 250625A: NOT z-band upper limit
  99. GRB 250625A: SVOM/VT optical confirmation
  100. GRB 250620B: Fermi GBM Observation

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