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"

36397 results found.

  1. GRB 241009A: LCO optical upper limits
  2. GRB 241013B: SVOM/GRM observation
  3. Fermi GRB 241013B: Global MASTER-Net observations report
  4. GRB 241013B: Fermi GBM Final Real-time Localization
  5. GRB 241013A: a long GRB detected by INTEGRAL
  6. GRB 241013A: Fermi GBM Final Real-time Localization
  7. Fermi Gamma-ray Burst Monitor GRB trigger 750372658/241011869 (GRB 241011A) is not a GRB
  8. GRB 241011A: Fermi GBM Final Real-time Localization
  9. GRB 241009A: GRANDMA optical upper limits
  10. GRB 241009A: Swift-XRT afterglow detection
  11. GRB 241010A: JinShan optical observations and potential host galaxy
  12. GRB 241006A: ATCA Radio Upper Limits
  13. GRB 241010A: Swift-XRT refined Analysis
  14. Fermi Gamma-ray Burst Monitor trigger 750303285/241011066 is not a GRB
  15. Fermi Gamma-ray Burst Monitor trigger 750291012/241010924 is not a GRB
  16. Swift GRB 241010A: Global MASTER-Net observations report
  17. GRB 241010A: J-band observations with WINTER
  18. Fermi GRB 241010B: Global MASTER-Net observations report
  19. GRB 241010B: Fermi GBM Final Real-time Localization
  20. IceCube-241006A: Upper limits from a search for additional neutrino events in IceCube
  21. GRB 241010A: Enhanced Swift-XRT position
  22. GRB 241010A: LCO optical observations
  23. GRB 241010A: Swift detection of a burst with an optical counterpart
  24. GRB 241006A: Swift-BAT refined analysis
  25. GRB 241009A: Swift ToO observations
  26. GRB 241009A : Detection of a long duration GRB by SVOM/ECLAIRs
  27. GRB 241008A: Fermi GBM Observation
  28. GRB 241008A: Fermi-LAT detection
  29. GRB 241002B: Swift-XRT afterglow detection
  30. GRB 241002A: NOT optical upper limits
  31. Fermi GRB 241008A: Global MASTER-Net observations report
  32. GRB 241008A: BALROG localization (Fermi Trigger 750117609 / GRB 241008917)
  33. GRB 241008A: Fermi GBM Final Real-time Localization
  34. GRB 241006A: GRANDMA optical upper limits
  35. EP240930a / GRB 240930B: CrAO ZTSH optical upper limit
  36. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  37. GRB 240910A: LBT optical observations
  38. EP trigger ID 01709065118: KAIT confirmation of the stellar flare
  39. GRB 241006A: Swift-XRT refined Analysis
  40. GRB 240821A: Host galaxy redshift from VLT/X-shooter
  41. GRB 241006A: PRIME near-infrared upper limits
  42. GRB 241006A: Swift/UVOT Upper Limits
  43. GRB 241006A: SVOM/VT follow-up and optical upper limit
  44. GRB 241001A: Swift-XRT afterglow detection
  45. GRB 241006A: Enhanced Swift-XRT position
  46. GRB 241006A: Swift detection of a burst
  47. GRB 240930B: SVOM/C-GFT optical upper limit
  48. GRB 241004A: SVOM/GRM observation
  49. GRB 240930B / EP 240930a: SVOM/GRM observation
  50. GRB 241001A : ECLAIRs spectral analysis and XRF classification
  51. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  52. GRB 241002B: Fermi GBM Observation
  53. GRB 241002B: Swift-XRT observations
  54. GRB 241002C: SVOM/C-GFT optical upper limit
  55. GRB 241002A: Swift-BAT refined analysis
  56. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  57. GRB 241002B: Swift ToO observations
  58. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  59. Konus-Wind detection of GRB 240926A
  60. GRB 241002B: PRIME near-infrared detection
  61. GRB 241002C: Swift ToO observations
  62. Fermi-GBM Sub-Threshold Detection of GRB 241002D
  63. IPN triangulation of GRB 240930B / EP 240930a
  64. GRB 241001A : SVOM/VT optical detection
  65. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  66. GRB 241002D: SVOM/GRM observation
  67. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  68. GRB 240930B: CALET Gamma-Ray Burst Monitor detection
  69. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  70. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  71. GRB 241002C : MITSuME Akeno optical upper limits
  72. LIGO/Virgo/KAGRA S240925n: Updated Sky localization
  73. NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
  74. GRB241001A: REM optical/NIR upper limits
  75. GRB 241002A: Swift/UVOT Upper Limits
  76. GRB 241002A: Swift-XRT refined Analysis
  77. GRB 241002A: LCOGT Optical Upper Limits
  78. GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
  79. GRB 241001A: Swift/UVOT Detection
  80. GRB 241001A: VLT/X-shooter redshift
  81. GRB 241002B: GOTO optical counterpart candidate
  82. GRB 241002C : Detection of a long soft transient by SVOM/ECLAIRs
  83. GRB 241001A: correction to GCN 37667
  84. GRB 240929A: Liverpool Telescope prompt followup observations
  85. Fermi GRB 241002B: Global MASTER-Net observations report
  86. GRB 241001A: Swift-XRT observations
  87. GRB 241002B: Fermi GBM Final Real-time Localization
  88. GRB241001A: optical afterglow candidate
  89. GRB 241002A: 1.5m OSN optical upper limit
  90. GRB 241002A: Enhanced Swift-XRT position
  91. GRB 241001A: BOOTES-6/DPRT optical upper limit
  92. GRB 241002A: Swift detection of a burst
  93. GRB 240930B: Fermi GBM Observation
  94. GRB 241001A: Swift ToO observations
  95. GRB 240930B: GRBAlpha detection
  96. GRB 240929A: GRBAlpha detection
  97. EP240930a : KAIT optical upper limit
  98. GRB 241001A : Detection of a soft transient by ECLAIRs onboard SVOM
  99. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  100. EP240930a: EP-FXT follow-up observation update

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