Skip to main content
End of Swift Science Operations, CHIME Notices Unavailable During Upgrade. See news and announcements

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"

27309 results found.

  1. GRB 191017B: Swift-BAT refined analysis
  2. GRB 191017B: Swift/UVOT Upper Limits
  3. GRB 191017B: Swift-XRT refined Analysis
  4. Fermi trigger No 593045905: Global MASTER-Net observations report
  5. GRB 191016A: Swift/UVOT Detection
  6. GRB 191017C: Fermi GBM Final Real-time Localization
  7. GRB 191017B: Swift detection of a burst
  8. GRB 191017A: Fermi GBM Final Localization
  9. GRB191016A: MITSuME Okayama optical observation
  10. GRB 191016A: early time BOOTES Network and follow-up 1.5m OSN optical observations
  11. 191017A: BALROG localization (Fermi Trigger 592997024 / GRB 191017391)
  12. GRB 191016A: RATIR Optical and NIR Observations
  13. Baksan Neutrino Observatory Alert 191016.51: Global MASTER-Net observations report
  14. GRB 191016A: Optical limit by Ondrejov D50
  15. GRB 191016A: Swift-BAT refined analysis
  16. GRB 191016A: COATLI Optical Observations and Detection of the Afterglow
  17. Swift GRB191016.17: Global MASTER-Net observations report
  18. GRB 191016A: Swift detection of a burst
  19. Fermi trigger No 592818648: Global MASTER-Net observations report
  20. ANTARES 191011A: MASTER optical observation befor and after trigger
  21. GRB 191011A: Swift-BAT refined analysis
  22. GRB 191011A: Swift/UVOT Detection
  23. GRB 191011A: RATIR Optical and NIR Observations
  24. GRB 191011A: Fermi GBM observation
  25. GRB 19011A: Optical Afterglow Detection with LCO
  26. GRB 191011A: Swift-XRT refined Analysis
  27. GRB 191009A: Insight-HXMT/HE detection
  28. GRB 191011A: BALROG localization (Fermi Trigger 592461363 / GRB 191011192)
  29. GRB 191011A: GROND Detection of the Optical/NIR afterglow
  30. GRB 191011A: VLT X-shooter redshift from RRM Observations
  31. Swift GRB191011.19: Global MASTER-Net observations report
  32. Swift GRB191011.19: Global MASTER-Net OT detection
  33. GRB 191011A: Swift detection of a burst with an optical counterpart
  34. GRB 191011A: Fermi GBM Final Real-time Localization
  35. GRB 191009A: BALROG localization (Fermi Trigger 592297741 / GRB 191009298)
  36. GRB 191009A: Fermi GBM Final Real-time Localization
  37. Fermi trigger No 592211224: Global MASTER-Net observations report
  38. GRB 191004A: CALET Gamma-Ray Burst Monitor detection
  39. Fermi trigger No 592211224: Global MASTER-Net observations report
  40. GRB 191008A: Fermi GBM Final Real-time Localization
  41. GRB 191004B: Swift/UVOT Detection
  42. GRB 191004B: Continued Optical Afterglow Monitoring with LCO
  43. Fermi/GBM observation of a bright burst from magnetar SGR 1935+2154
  44. GRB 191004A: Swift/UVOT Detection
  45. GRB 191004A: Optical Detection with LCO
  46. LIGO/Virgo S190930s: no counterpart candidate in the SVOM/GWAC observations
  47. LIGO/Virgo S190930t: Swift XRT observations, no secure afterglow found
  48. GRB 190928A: AstroSat CZTI detection
  49. GRB 191004B: Swift-XRT refined Analysis
  50. GRB 191004B: GROND Detection of the Optical/NIR Afterglow
  51. GRB 191004A: GROND Upper limits
  52. GRB 191004A: Swift-XRT refined Analysis
  53. GRB 191004B: Swift-BAT refined analysis
  54. GRB 191004A: Swift-BAT refined analysis
  55. GRB 191004B: Optical Afterglow Detection with LCO
  56. Swift GRB191004.9: Global MASTER-Net OT detection
  57. GRB 191004B: Swift detection of a burst with an optical counterpart
  58. GRB 191004A: Swift detection of a burst with an optical detection
  59. Swift GRB191004.75: Global MASTER-Net OT detection
  60. GRB 191001B: Optical Upper Limits with LCO
  61. LIGO/Virgo S190930t: Continued Swift/UVOT observations of Swift J221951-484240
  62. GRB 191001A: Fermi GBM observation
  63. LIGO/Virgo S190930t: Upper limits from Insight-HXMT/HE observations
  64. LIGO/Virgo S190930s: Upper limits from Insight-HXMT/HE observations
  65. GRB 191001B: Swift-BAT refined analysis
  66. IPN triangulation of GRB 191001A
  67. LIGO/Virgo S190930t: No neutrino candidates at Pierre Auger Observatory
  68. GRB 191001A: RATIR Optical and NIR Observations
  69. LIGO/Virgo S190930s: no counterpart candidates in SAGUARO/CSS observations
  70. LIGO/Virgo S190930s: No counterpart candidates in KAIT observations
  71. GRB 191001A: DDOTI Optical Counterpart Candidate
  72. IceCube Alert 191001.84: Global MASTER-Net observations report
  73. GRB 191001B: Swift detection of a burst
  74. LIGO/Virgo S190930t: Candidates from the Zwicky Transient Facility
  75. LIGO/Virgo S190930t: No counterpart candidates in Fermi-LAT observations
  76. LIGO/Virgo S190930t and S190930s: MASTER optical observation and optical transient
  77. Fermi trigger No 591604915: Global MASTER-Net observations report
  78. LIGO/Virgo S190930s: No counterpart candidates in Fermi-LAT observations
  79. GRB 191001A: BALROG localization (Fermi Trigger 591604915 / GRB 191001279)
  80. GRB 191001A: Fermi GBM Final Real-time Localization
  81. LIGO/Virgo S190930t: Upper limits from CALET observations.
  82. LIGO/Virgo S190930s: Upper limits from CALET observations.
  83. LIGO/Virgo S190930t: Coverage and upper limits from MAXI/GSC observations
  84. LIGO/Virgo S190930s: no counterpart candidates in the Swift/BAT observations
  85. LIGO/Virgo S190930t: no counterpart candidates in the Swift/BAT observations
  86. LIGO/Virgo S190930t: Upper limits from Fermi-GBM Observations
  87. LIGO/Virgo S190930s: Upper limits from Fermi-GBM Observations
  88. LIGO/Virgo S190930t: No counterpart candidates in HAWC observations
  89. LIGO/Virgo S190928c: Retraction of GW unmodeled transient candidate
  90. GRB 190928A: Insight-HXMT/HE detection
  91. LIGO/Virgo S190930s: Coverage and upper limits from MAXI/GSC observations
  92. LIGO/Virgo S190930t: Identification of a GW compact binary merger candidate
  93. LIGO/Virgo S190930t: Global MASTER-Net observations report
  94. LIGO/Virgo S190930s: Identification of a GW compact binary merger candidate
  95. LIGO/Virgo S190930s: Global MASTER-Net observations report
  96. Fermi trigger No 591532362: Global MASTER-Net observations report
  97. Konus-Wind observation of GRB 190928A
  98. GRB 190928A: MASTER optical observations
  99. GRB 190930A: Fermi GBM Final Real-time Localization
  100. GRB 190928A: CALET Gamma-Ray Burst Monitor detection

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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