Skip to main content
New Announcement Feature, Code of Conduct, Circular Revisions. 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').

17102 results found.

  1. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  2. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  3. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  4. GRB 240513A: Tiled Swift observations
  5. GRB 240513A: Fermi-LAT detection
  6. GRB 240511A: Fermi GBM Observation
  7. GRB 240511A: Swift-BAT refined analysis
  8. GRB 240511A: J-band observations with WINTER
  9. GRB 240511A: Enhanced Swift-XRT position
  10. GRB 240511A : MITSuME Akeno optical upper limits
  11. GRB 240511A: Swift-XRT refined Analysis
  12. Swift GRB 240511A: Global MASTER-Net observations report
  13. GRB 240511A: Prompt enhanced Swift-XRT position
  14. GRB 240511A: Swift detection of a burst
  15. GRB 240504A: Fermi GBM Observation
  16. IPN triangulation of GRB 240504A
  17. GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  18. GRB 240415A 1.3m DFOT Optical upper limit
  19. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  20. LVK S240422ed: Further Swift-XRT followup of three sources
  21. LIGO/Virgo/KAGRA S240422ed: Magellan Follow-up Observations of Swift/XRT candidates
  22. LIGO/Virgo/KAGRA S240422ed: 2.5m PRL Telescope follow-up of the Swift/XRT source S240422ed_X190
  23. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  24. LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limits for Swift/XRT candidates
  25. GRB 240419B: Swift-BAT refined analysis
  26. GRB 240421B: Swift-BAT refined analysis
  27. LIGO/Virgo/KAGRA S240422ed: Himalayan Chandra Telescope follow-up of the Swift/XRT source S240422ed_X101
  28. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  29. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
  30. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  31. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  32. LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Three Potential Electromagnetic Counterparts Reported So Far
  33. GRB 240421B: GRBAlpha detection
  34. LIGO/Virgo/KAGRA S240422ed: WINTER J-band upper limits on the Swift/XRT source S240422ed_X61
  35. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
  36. GRB 240419A: Swift-BAT refined analysis
  37. GRB 240418A: Swift-BAT refined analysis
  38. LXT240402A/GRB240402B: Chandra X-ray detection
  39. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
  40. GRB 240419B : MITSuME Akeno optical upper limits
  41. GRB 240415B: Swift-XRT observations
  42. GRB 240415A: Swift-XRT refined Analysis
  43. GRB 240421B: AstroSat CZTI detection
  44. GRB240421B: Zadko Observations
  45. Swift GRB 240421B: Global MASTER-Net observations report
  46. GRB 240421B: Fermi GBM Observation
  47. GRB 240421B: Swift-XRT refined Analysis
  48. GRB240421B: BOOTES-5/JGT optical upper limit
  49. GRB 240421B: Swift/UVOT Upper Limits
  50. GRB 240421B: Enhanced Swift-XRT position
  51. GRB 240421B: Swift detection of a burst
  52. GRB240419A: Skynet Optical Afterglow Analysis
  53. GRB 240419B: Swift/UVOT Upper Limits
  54. GRB 240419A: Swift/UVOT Upper Limits
  55. GRB 240419B: Swift-XRT refined Analysis
  56. Swift GRB 240419B: Global MASTER-Net observations report
  57. GRB 240419B: Enhanced Swift-XRT position
  58. Swift GRB 240419A: Global MASTER-Net observations report
  59. GRB 240418A: Swift/UVOT Upper Limits
  60. GRB 240419A: Swift-XRT refined Analysis
  61. GRB 240418A: Swift-XRT refined Analysis
  62. GRB 240419B: Swift detection of a burst
  63. GRB 240411B: Swift/UVOT Detection
  64. GRB240418A: YAHPT Upper Limits
  65. GRB 240419A: Enhanced Swift-XRT position
  66. GRB 240419A: Prompt enhanced Swift-XRT position
  67. GRB 240419A: Swift detection of a burst
  68. GRB 240418A: TSHAO Zeiss-1000 optical upper limit
  69. GRB 240418A: Enhanced Swift-XRT position
  70. Swift GRB240418.85: Global MASTER-Net observations report
  71. GRB 240418A: Swift detection of a burst
  72. Improved IPN triangulation of GRB 240411A
  73. GRB 240415A: Glowbug gamma-ray detection
  74. GRB 240414A: Glowbug gamma-ray detection
  75. GRB 240415B: GECAM-B detection
  76. GRB 240415A: Swift-BAT refined analysis
  77. GRB 240411A: Glowbug gamma-ray detection
  78. GRB 240414A: Swift-BAT refined analysis
  79. GRB 240414A: AbAO optical upprer limit
  80. GRB 240415A: Swift/UVOT Detection
  81. GRB 240415A: Fermi GBM Observation
  82. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  83. GRB 240415A: Enhanced Swift-XRT position
  84. GRB 240415B: Swift ToO observations
  85. GRB 240415B: Swift/BAT-GUANO Correction
  86. GRB 240415B: Swift/BAT-GUANO arcminute localization of a short burst
  87. GRB 240414A: Fermi GBM Observation
  88. GRB 240414A: Swift/UVOT Detection
  89. LXT 240402A/GRB 240402B: Swift follow-up observations
  90. GRB 240414A: Mondy optical observations
  91. GRB 240415A: Prompt Swift-XRT observations
  92. GRB 240415A: Swift detection of a burst
  93. GRB 240414A: Swift-XRT refined Analysis
  94. GRB 240414A: Enhanced Swift-XRT position
  95. GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  96. GRB 240414A: Skynet Optical Afterglow Observations
  97. Swift GRB 240414A: Global MASTER-Net observations report
  98. IPN triangulation of GRB 240410A
  99. IPN triangulation of GRB 240411A
  100. GRB 240414A : MITSuME Akeno optical upper limits

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