Skip to main content
New! Browse Circulars by Event, Advanced Search, Sample Codes, Schema Release. See news and announcements

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"

10769 results found.

  1. GRB 231020B: AstroSat CZTI detection
  2. GRB 231024A: Fermi GBM Final Localization
  3. Fermi trigger No 719846439: Global MASTER-Net observations report
  4. The photometry of the transient in Messier 31 field: GMG observation
  5. GRB 231018A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  6. LIGO/Virgo/KAGRA S231020bw: Upper limits from Swift/BAT-GUANO
  7. LIGO/Virgo/KAGRA S231021az: Coverage and upper limits from MAXI/GSC observations
  8. GRB 231020A: Fermi GBM Detection
  9. GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
  10. GRB 231020B: BALROG localization (Fermi Trigger 719530557 / GRB 231020900)
  11. GRB 231020B: Fermi GBM Final Real-time Localization
  12. GRB 231020A: BALROG localization (Fermi Trigger / GRB 231020790)
  13. Fermi GRB 231020A: Global MASTER-Net observations report
  14. LIGO/Virgo/KAGRA S231020bw: Identification of a GW compact binary merger candidate
  15. GRB 231020A: Fermi GBM Final Real-time Localization
  16. LIGO/Virgo/KAGRA S231020ba: Coverage and upper limits from MAXI/GSC observations
  17. LIGO/Virgo/KAGRA S231020ba: Identification of a GW compact binary merger candidate
  18. Konus-Wind detection of GRB 231018A
  19. GRB 231017A: GOTO optical upper limits
  20. GRB 231015A: AstroSat CZTI detection
  21. GRB 231017A: Swift/BAT-GUANO candidate arcminute localization of a burst
  22. Fermi-LAT gamma-ray observations of IceCube-231014A
  23. LIGO/Virgo/KAGRA S231014r: Upper limits from Swift/BAT-GUANO
  24. GRB 231012A: Fermi GBM Final Real-time Localization
  25. LIGO/Virgo/KAGRA S231005j: Upper limits from Swift/BAT-GUANO
  26. LIGO/Virgo/KAGRA S231008ap: Identification of a GW compact binary merger candidate
  27. Fermi-LAT gamma-ray observations of IceCube-231004A
  28. LIGO/Virgo/KAGRA S231001aq: Upper limits from Swift/BAT-GUANO
  29. LIGO/Virgo/KAGRA S230930al: Upper limits from Swift/BAT-GUANO
  30. LIGO/Virgo/KAGRA S230928cb: Upper limits from Swift/BAT-GUANO
  31. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-230927A
  32. Konus-Wind detection of GRB 230919A
  33. LIGO/Virgo/KAGRA S230924an: Upper limits from Swift/BAT-GUANO
  34. LIGO/Virgo/KAGRA S230920al: Upper limits from Swift/BAT-GUANO
  35. LIGO/Virgo/KAGRA S230919bj: Upper limits from Swift/BAT-GUANO
  36. LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
  37. GRB 230812B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
  38. LIGO/Virgo/KAGRA S230917af: GRAWITA wide-field observations
  39. GRB 230919A: Swift/BAT-GUANO detection of a possibly short burst outside the coded FOV
  40. GRB 230812B : optical observations from MISTRAL at Observatoire de Haute-Provence
  41. GRB 230919A: AstroSat CZTI detection
  42. LIGO/Virgo/KAGRA S230920al: Identification of a GW compact binary merger candidate
  43. GRB 230918B: GOTO detection of a fast-rising transient in the GBM localisation region
  44. LIGO/Virgo S230917af: Swift XRT observations, 6 X-ray sources
  45. GRB 230917A: AstroSat CZTI detection
  46. LIGO/Virgo/KAGRA S230917af: MAXI/GSC observations
  47. Fermi trigger No 716572242: Global MASTER-Net observations report
  48. Fermi-LAT gamma-ray observations of IceCube-230914A
  49. LIGO/Virgo/KAGRA S230914ak: Upper limits from Swift/BAT-GUANO
  50. Swift GRB230916.11: Global MASTER-Net observations report
  51. Fermi trigger No 716449174: Global MASTER-Net observations report
  52. Fermi trigger No 716419312: Global MASTER-Net observations report
  53. GRB 230913A: Fermi GBM Observation
  54. Swift GRB230913.70: Global MASTER-Net observations report
  55. GRB 230911B: AstroSat CZTI detection
  56. GRB 230911C: Swift-XRT refined Analysis
  57. GRB 230911D: Fermi-LAT detection
  58. GRB230911C: LCOGT Optical Upper Limits
  59. GRB 230908A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  60. Konus-Wind detection of GRB 230811D
  61. GRB 230911C: Swift detection of a burst
  62. GRB 230906A: AstroSat CZTI detection
  63. GRB 230908A: GRBAlpha detection
  64. GRB 230908A: AstroSat CZTI detection
  65. Konus-Wind detection of GRB 230906A (short)
  66. IPN triangulation of GRB 230906A (short)
  67. GRB 230905B: AstroSat CZTI detection
  68. Fermi GRB 230906A: Global MASTER-Net observations report
  69. GRB 230905B: GECAM-C detection of a long burst
  70. GRB 230903A: Swift-XRT refined Analysis
  71. GRB 230904C: Fermi GBM Final Localization
  72. Fermi trigger No 715552087: Global MASTER-Net observations report
  73. Fermi trigger No 715429986: Global MASTER-Net observations report
  74. GRB 230903A: LCOGT Optical Upper Limits
  75. GRB 230903A: Swift detection of a burst
  76. Swift GRB230903.72: Global MASTER-Net observations report
  77. GRB 230828A: AstroSat CZTI detection
  78. GRB 230827A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  79. Fermi trigger No 714809315: Global MASTER-Net observations report
  80. Fermi GRB 230827A: Global MASTER-Net observations report
  81. Swift J1727.8-1613 (GRB 230824A): Leavitt Observatory optical observations
  82. GRB 230826A: Mondy optical observations
  83. Swift GRB230826.81: Global MASTER-Net observations report
  84. LIGO/Virgo/KAGRA S230825k: Upper limits from Swift/BAT-GUANO
  85. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
  86. Trigger 1187207: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  87. Trigger 1187203: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  88. Trigger 1187142: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  89. MAXI/GSC detection of Swift J1727.8-1613 (GRB 230824A)
  90. IBAS trigger 10375 is not a GRB
  91. Integral GRB230824.72: Global MASTER-Net observations report
  92. GRB 230824B: AstroSat CZTI detection
  93. GRB 230824A: Swift detection of a burst
  94. LIGO/Virgo/KAGRA S230822bm: Upper limits from Swift/BAT-GUANO
  95. GRB 230818B: AstroSat CZTI detection
  96. GRB 230812B: Assy optical observations, possible SN rise
  97. GRB 230812B: SAO RAS RC-500 and Zeiss-1000 observations
  98. Konus-Wind detection of GRB 230818A
  99. GRB 230820A: AstroSat CZTI detection
  100. LIGO/Virgo/KAGRA S230820bq: Identification of a GW compact binary merger candidate

Advanced

Download all Circulars as a .tar.gz archive:
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov