Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! 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"

28054 results found.

  1. Continued Chandra observations of GW170817 at ~3.3 years since merger
  2. Konus-Wind detection of two bright bursts from SGR 1935+2154
  3. GRB 140330A: Swift-XRT refined Analysis
  4. GRB 140320B: Swift-XRT refined Analysis
  5. GRB 210126A: AstroSat CZTI detection
  6. GRB 210123A: AstroSat CZTI detection
  7. IPN triangulation of a bright burst from SGR 1935+2154
  8. GECAM detection of a short burst probably from SGR 1935+2154
  9. GRB 210120A: Fermi GBM detection
  10. HAWC Transient event on 2021/01/25
  11. GRB 210126A: GECAM detection
  12. GRB 210126A: BALROG localization (Fermi Trigger / GRB 210126417)
  13. GRB 210124B: Insight-HXMT/HE detection
  14. GECAM detection of a burst possibly from the X-ray burster 4U 0614+09 or GRB 210124A
  15. GRB 210123A: Insight-HXMT/HE detection
  16. GRB 210121A: GECAM detection
  17. GRB 210121A: Insight-HXMT/HE detection
  18. GRB 210120A : 1.3m DFOT optical observations
  19. GRB 210120A(MASTER OT J105242.66+152355.0 / AT2021axc): Mondy optical observations
  20. GRB 210116: AstroSat LAXPC detection
  21. GRB 210104A: 3.6m DOT optical upper limit
  22. GRB 210120A: BALROG localization (Fermi Trigger 632819449 / GRB 210120299)
  23. GRB 210112A: 3.6m DOT optical detection
  24. GRB 210119A (Swift J1851.2-6148): Swift-BAT refined analysis
  25. ZTF21aaeyldq: GROND observations
  26. GRB 210119A: Insight-HXMT/HE detection
  27. ZTF21aaeyldq: LBT near-infrared observations
  28. GRB 210112A: Insight-HXMT/HE detection
  29. Short Fermi GRB 210119A or new SGR Swift J1851.2-6148: Possible MASTER Short OT detection
  30. ZTF21aaeyldq: KPED observations
  31. Correction to GCN 29288: NuEm-210111A: No counterpart candidates in INTEGRAL SPI-ACS observation
  32. GRB 201221D: near-infrared observation with LBT
  33. ZTF21aaeyldq: NOT optical observations
  34. ZTF21aaeyldq: Lowell Discovery Telescope observations
  35. ZTF21aaeyldq: observations with the 3.6m Devasthal Optical Telescope
  36. GRB 201015A: evidence of supernova in LBT spectra
  37. GRB 210112A: Swift/UVOT Detection
  38. GRB 210112A: Mondy optical observations
  39. GRB 210104A: AstroSat CZTI detection
  40. NuEm-210111A: MAXI/GSC upper limit
  41. GRB 210112A: Swift-BAT refined analysis
  42. GRB 210112A: OSN Reddened Afterglow Detection
  43. GRB 210112A: Swift-XRT refined Analysis
  44. NuEm-210111A : No neutrino counterpart in ANTARES
  45. GRB 210112A: Kitab a optical upper limit
  46. GRB 210104A: AROMA-N Optical Afterglow Detection
  47. GRB 210112A: Enhanced Swift-XRT position
  48. GRB 210112A: Swift detection of a burst with an optical counterpart
  49. NuEm-210111A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  50. MAXI GRB210110.64: Global MASTER-Net observations report
  51. GRB 210110A: MAXI/GSC detection
  52. GRB 210109A: MAXI/GSC detection
  53. GRB 201227A: continued Chilescope confirmation of variability of possible optical counterpart, redshift estimating
  54. Correction to GCN 29278: GRB 201216C XRT refined analysis
  55. GRB 210108A: BALROG localization (Fermi Trigger 631793415 / GRB 210108424)
  56. GRB 201216C: Swift-XRT refined Analysis
  57. GRB 210104A: SAO RAS optical observations
  58. GRB 201227A: ASIM observation
  59. GRB 210104A: GMG observations
  60. GRB210104A: VIRT optical transient detection.
  61. GRB 210104A: SARA-KP 0.9m Optical Afterglow Detection
  62. GRB 210102B: further Swift-XRT observations
  63. GRB 210102B: Assy optical afterglow identification
  64. GRB 210104A: iTelescope optical upper limit
  65. GRB 210104B: Swift-BAT refined analysis
  66. GW170817: HST observations at 3.4 years from merger
  67. GRB 210104A: early ATLAS detections of the bright afterglow
  68. GRB 210104A: Swift-XRT refined Analysis
  69. GRB 210104B: Swift/UVOT Upper Limits
  70. GRB 210104B: Swift-XRT refined Analysis
  71. GRB 210104B: Assy optical upper limit
  72. GRB 210104A: DOAO optical afterglow observations
  73. GRB 210104B: Enhanced Swift-XRT position
  74. GRB 210104A: Nanshan/NEXT optical powerlaw decay
  75. GRB 210104A: Swift-BAT refined analysis
  76. GRB 210104B: Nanshan/NEXT optical upper limit
  77. GRB 210104A: Swift/UVOT Detection
  78. GRB 210104A: Fermi GBM detection
  79. GRB 210104A: Enhanced Swift-XRT position
  80. GRB 210104B: Swift detection of a burst
  81. GRB 210104A: MITSuME Ishigaki optical observation
  82. GRB 210104A: MITSuME Akeno optical observation
  83. GRB 210104A: BALROG localization (Fermi Trigger 631452424 / GRB 210104477)
  84. GRB 210104A: Swift detection of a burst with a bright optical counterpart
  85. GRB 210102C: Swift-BAT refined analysis
  86. GRB 210102B: Swift-XRT observations
  87. GRB 210102C: Fermi GBM detection
  88. MAXI GRB210102.38: Global MASTER-Net observations report
  89. GRB 210102B: MAXI/GSC detection
  90. INTEGRAL Weak #8913: AROMA-N Optical Observation
  91. Swift Trigger 1015615 is not a GRB
  92. Fermi trigger No 631119348: Global MASTER-Net observations report
  93. GRB 210101A: BALROG localization (Fermi Trigger 631205591 / GRB 210101620)
  94. GRB 210101A: Fermi GBM Final Real-time Localization
  95. GRB 201229A: Swift/UVOT Detection
  96. Fermi trigger No 631104264: Global MASTER-Net observations report
  97. GRB 201216C: TSHAO, Terskol, Mondy optical upper limits
  98. GRB 201227A: Chilescope optical observations, possible optical counterpart
  99. GRB 201227A: GRAWITA VST-ESO PARANAL observations
  100. GRB 201229A: AbAO optical afterglow detection, TSHAO optical upper limit

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