Skip to main content
JSON Notices via Email, Kafka Cron Jobs, Submitter Profile, GCN is Hiring. 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"

26119 results found.

  1. EP241021a: VLT/FORS2 redshift z = 0.75
  2. EP241021a: KAIT optical observations
  3. EP241021a: EP-FXT follow-up observation update
  4. GRB241017A: 1.3m DFOT optical upper limit
  5. GRB 241018A: 1.3m DFOT Optical upper limit
  6. GRB 241018A: EP-FXT afterglow detection
  7. GRB 241018A: BOOTES-4/MET optical upper limit
  8. GRB 241018A: Mondy optical upper limit
  9. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  10. GRB 241018A: GROWTH-India telescope optical upper limit
  11. GRB 241018A: Swift-XRT observations
  12. GRB 241018A: REM optical/NIR upper limits
  13. GRB 241018A: NOT optical observations
  14. GRB 241018A: LCO/0.4m optical upper limits
  15. GRB 241018A: Swift ToO observations
  16. GRB 241006A: VIRT Optical Upper Limit
  17. GRB 240727A: VIRT Optical Upper Limit
  18. GRB 241018A: X-ray afterglow candidate observed by MXT
  19. GRB 241016B: Fermi GBM Observations
  20. GRB 241017A: Swift-XRT observations
  21. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  22. GRB 241001A: EP-FXT afterglow detection
  23. GRB 241017A: GROWTH-India Telescope optical upper limit
  24. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  25. GRB 241017A: Swift ToO observations
  26. GRB 241010A: Swift-BAT refined analysis
  27. GRB 241013B: Fermi GBM Observation
  28. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  29. GRB 241009A: LCO optical upper limits
  30. GRB 241009A: GRANDMA optical upper limits
  31. GRB 241009A: Swift-XRT afterglow detection
  32. GRB 241010A: JinShan optical observations and potential host galaxy
  33. GRB 241006A: ATCA Radio Upper Limits
  34. GRB 241010A: Swift-XRT refined Analysis
  35. Swift GRB 241010A: Global MASTER-Net observations report
  36. GRB 241010A: J-band observations with WINTER
  37. GRB 241010A: Enhanced Swift-XRT position
  38. GRB 241010A: LCO optical observations
  39. GRB 241010A: Swift detection of a burst with an optical counterpart
  40. GRB 241006A: Swift-BAT refined analysis
  41. GRB 241009A: Swift ToO observations
  42. GRB 241002B: Swift-XRT afterglow detection
  43. GRB 241002A: NOT optical upper limits
  44. GRB 241006A: GRANDMA optical upper limits
  45. GRB 240910A: LBT optical observations
  46. GRB 241006A: Swift-XRT refined Analysis
  47. GRB 241006A: PRIME near-infrared upper limits
  48. GRB 241006A: Swift/UVOT Upper Limits
  49. GRB 241006A: SVOM/VT follow-up and optical upper limit
  50. GRB 241001A: Swift-XRT afterglow detection
  51. GRB 241006A: Enhanced Swift-XRT position
  52. GRB 241006A: Swift detection of a burst
  53. Swift GRB241006.91: Global MASTER-Net observations report
  54. GRB 240930B: SVOM/C-GFT optical upper limit
  55. GRB 240930B / EP 240930a: SVOM/GRM observation
  56. GRB 241002B: Fermi GBM Observation
  57. GRB 241002B: Swift-XRT observations
  58. GRB 241002A: Swift-BAT refined analysis
  59. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  60. GRB 241002B: Swift ToO observations
  61. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  62. GRB 241002C: Swift ToO observations
  63. IPN triangulation of GRB 240930B / EP 240930a
  64. GRB 240930B: CALET Gamma-Ray Burst Monitor detection
  65. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  66. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  67. GRB241001A: REM optical/NIR upper limits
  68. GRB 241002A: Swift/UVOT Upper Limits
  69. GRB 241002A: Swift-XRT refined Analysis
  70. GRB 241002A: LCOGT Optical Upper Limits
  71. GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
  72. GRB 241001A: Swift/UVOT Detection
  73. GRB 241001A: VLT/X-shooter redshift
  74. GRB 241001A: correction to GCN 37667
  75. GRB 241001A: Swift-XRT observations
  76. GRB241001A: optical afterglow candidate
  77. GRB 241002A: 1.5m OSN optical upper limit
  78. GRB 241002A: Enhanced Swift-XRT position
  79. GRB 241002A: Swift detection of a burst
  80. GRB 240930B: Fermi GBM Observation
  81. GRB 241001A: Swift ToO observations
  82. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  83. EP240930a: EP-FXT follow-up observation update
  84. SVOM/GRM detection of a burst from SGR Swift J1818.0-1607
  85. AMON NuEM 240926A: Swift XRT Follow-up
  86. Konus-Wind detection of GRB 240912A
  87. Swift Trigger 1256950 is probably not a GRB
  88. LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
  89. LIGO/Virgo/KAGRA S240920dw: Upper limits from Swift/BAT-GUANO
  90. LIGO/Virgo/KAGRA S240919bn: Upper limits from Swift/BAT-GUANO
  91. GRB 240529A: FRAM-ORM early optical afterglow observations reveal plateau and rebrightening
  92. GW S240915b and S240919bn : Swift UVOT follow-up
  93. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  94. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  95. LIGO/Virgo S240919bn: GOTO optical upper limits
  96. LIGO/Virgo S240919bn: Swift XRT observations, 10 X-ray sources
  97. EP240913A/GRB 240913C: AbAO optical upper limit
  98. GRB 240910A: further Swift observations and confirmation of afterglow
  99. EP240918a: Swift-XRT observation
  100. GRB 240916A: NOT optical observation

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