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"

45808 results found.

  1. GRB 241129A: Fermi GBM Observation
  2. GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
  3. GRB 241209D: REM optical/NIR upper limits
  4. Konus-Wind detection of GRB 241209D
  5. GRB 241209B: Swift-XRT afterglow detection
  6. GRB 241209C: Fermi GBM Observation
  7. GRB 241209A: Swift-XRT refined Analysis
  8. Fermi Gamma-ray Burst Monitor trigger 755485387 / 241210044 is not a GRB
  9. LIGO/Virgo/KAGRA S241210fu: Identification of a GW compact binary merger candidate
  10. EP241208a: Optical upper limit with Kinder observations
  11. GRB 241128A: CrAO ZTSh and Mondy AZT-33IK optical observations
  12. GRB 241209D: AstroSat CZTI detection
  13. GRB 241209A: EP-FXT follow-up observations
  14. GRB 241209B: SVOM/VT afterglow detection
  15. LIGO/Virgo/KAGRA S241210cw: Identification of a GW compact binary merger candidate
  16. EP241208a: Global MASTER-Net observations report
  17. EP241208a: EP-FXT follow-up observations
  18. LIGO/Virgo/KAGRA S241210d: Identification of a GW compact binary merger candidate
  19. Fermi trigger No 755485387: Global MASTER-Net observations report
  20. GRB 241207B: Fermi GBM Observation
  21. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  22. GRB 241209D: Swift-XRT refined Analysis
  23. GRB 241209D: Fermi GBM Observation
  24. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  25. GRB 241209D: COLIBRÍ detection of the afterglow
  26. GRB 241209A: COLIBRÍ Optical Upper Limit
  27. Fermi GRB 241209D: Global MASTER-Net observations report
  28. GRB 241209A: Fermi GBM Observation
  29. GRB 241209C: Swift/BAT-GUANO localization skymap of a burst
  30. GRB 241209A: GRANDMA/TAROT upper limit
  31. GRB 241209B: BOOTES-5 optical upper limit
  32. Swift GRB 241209D: Global MASTER-Net observations report
  33. Fermi GRB 241209C: Global MASTER-Net observations report
  34. Fermi GRB 241209E: Global MASTER-Net observations report
  35. GRB 241209E: Fermi GBM Final Real-time Localization
  36. GRB 241209B: Swift ToO observations
  37. LIGO/Virgo/KAGRA S241102br: continued GRAWITA observations and detection of an optical transient (AT2024adip)
  38. GRB 241209A: REM optical/NIR observations
  39. GRB 241209D: Enhanced Swift-XRT position
  40. GRB 241209C: AstroSat CZTI detection
  41. GRB 241209D: Swift detection of a burst
  42. GRB 241209D: Fermi GBM Final Real-time Localization
  43. GRB 241209A: VLT/X-shooter spectroscopy
  44. GRB 241209A: Enhanced Swift-XRT position
  45. GRB 241114B: cubesat Avion detection
  46. GRB 241209A: VLT optical observations
  47. Fermi GRB 241209A: Global MASTER-Net observations report
  48. GRB 241209C: Fermi GBM Final Real-time Localization
  49. GRB 241209A: GOTO optical upper limits
  50. EP241206a: 1.5m OSN optical limit
  51. GRB 241209A: Prompt enhanced Swift-XRT position
  52. GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
  53. EP241208a: EP detection of a fast X-ray transient
  54. GRB 241209A: Swift detection of a short burst
  55. Swift GRB241209.23: Global MASTER-Net observations report
  56. GRB 241209A: Fermi GBM Final Real-time Localization
  57. Fermi GRB 241207B: Global MASTER-Net observations report
  58. GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
  59. Fermi Gamma-ray Burst Monitor trigger 755277791/241207641 is not a GRB
  60. GRB 241201A: AstroSat CZTI detection
  61. GRB 241206A: DDOTI Upper Limit on the Afterglow
  62. AT2024adec: X-ray Upper Limits from EP-FXT Observation
  63. AT2024adec: X-ray Upper Limits from EP-FXT Observation
  64. EP241206a: BOOTES Global Network optical limits
  65. GRB 241207C: MASTER optical observations
  66. Fermi trigger No 755225799: Global MASTER-Net observations report
  67. GRB 241207C: Tiled Swift observations
  68. GRB 241207C: MAXI/GSC detection
  69. GRB 241207B: Fermi GBM Final Real-time Localization
  70. Fermi trigger No 755277791: Global MASTER-Net observations report
  71. Fermi GRB 241207A: Global MASTER-Net observations report
  72. EP241206a: Global MASTER-Net observations report
  73. EP241206a: EP detection of a fast X-ray transient
  74. GRB 241206A: Fermi GBM observation
  75. GRB 241206C: SVOM/GRM observation of a likely short burst
  76. GRB 241207A: Fermi GBM Final Real-time Localization
  77. GRB 241206A: Swift/BAT-GUANO localization skymap of a burst
  78. GRB 241206B: SVOM/MXT observations: a probable flare from the QSO 1ES 1959+650
  79. GRB 241206B: GWAC-F50A optical upper limit
  80. GRB 241206B: SVOM/ECLAIRs detection of a long soft transient
  81. EP241113a: Keck/LRIS spectroscopic observation and tentative redshift
  82. Fermi GRB 241206A: Global MASTER-Net observations report
  83. GRB 241206A: Fermi GBM Final Real-time Localization
  84. EP241201a: 1.6m Mephisto Optical Upper Limits
  85. GRB 241204A: COLIBRÍ Optical Upper Limit
  86. EP241202b: KAIT optical upper limit
  87. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  88. GRB 241204A: DDOTI Upper Limits on the Afterglow
  89. GRB 241204A: Fermi GBM Observation
  90. Fermi GRB 241204A: Global MASTER-Net observations report
  91. GRB 241130A: CALET Gamma-Ray Burst Monitor detection
  92. GRB 241128A : RAPAS follow-up observations
  93. GRB 241201A: GRBAlpha detection
  94. GRB 241204A: Fermi-LAT detection
  95. EP241202b: Upper limits from Fermi-GBM Observations
  96. IceCube-241127A: No transient candidates from the Zwicky Transient Facility
  97. EP241202b: Kinder optical counterpart candidate
  98. Fermi-GBM Sub-Threshold Detection of GRB 241128A
  99. GRB 241113B : RAPAS follow-up observation
  100. EP241201a: EP-FXT follow-up observations

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