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"
  1. GRB 240715A: Swift ToO observations
  2. Fermi GRB 240715A: Global MASTER-Net observations report
  3. GRB 240713A: optical upper limits from the INAF Asiago Observatory
  4. GRB 240715A: Fermi GBM Observation
  5. GRB 240712A ATCA radio observations
  6. GRB240715A: GRANDMA Optical Upper Limits
  7. IPN triangulation of GRB 240715A (short)
  8. GW s240422ed: Swift UVOT follow-up
  9. GRB 240712A: Swift/UVOT Upper Limits
  10. EP-WXT flaring star and the optical flaring activity during its decay phase
  11. JinShan confirmation of the EP-WXT source triggered on July 14th due to a flaring star
  12. The EP-WXT source triggered on July 14th is likely a flaring star
  13. GRB 240715A: Fermi GBM Final Real-time Localization
  14. GRB 240713A: Tiled Swift observations
  15. GRB 240713A: J-band upper limit from WINTER
  16. GRB 240713A: NOT optical upper limits on three EP/FXT candidates
  17. GRB 240713A: JinShan optical upper limits
  18. GRB 240713A: OHP/T120 optical upper limit
  19. GRB240713A: X-ray follow-up observation with EP-FXT (duplicate submission of GCN 36859)
  20. GRB240713A: X-ray follow-up observation with EP-FXT
  21. GRB 240713B: AstroSat CZTI detection of a long burst
  22. GRB240713A: Optical upper limit with Kinder observations
  23. Fermi Sub-threshold Observation of GRB240713A
  24. GRB240713A: TAROT and GRANDMA Observations of SVOM/ECLAIRs GRB240713A
  25. GRB240713A : The first probable GRB Located on-Board SVOM by ECLAIRs
  26. Fermi Gamma-ray Burst Monitor trigger 742413075/240711744 is not a GRB
  27. EP240708a: GSP optical upper limit
  28. GRB 240712A: Swift detection of a burst
  29. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  30. GRB 240711A: Fermi GBM Final Real-time Localization
  31. Fermi trigger No 742405878: Global MASTER-Net observations report
  32. LIGO/Virgo/KAGRA S240627by: Updated Sky localization and EM Bright Classification
  33. Fermi trigger No 742317942: Global MASTER-Net observations report
  34. EP240708a: KAIT optical upper limit
  35. Fermi GRB 240710A: Global MASTER-Net observations report
  36. GRB 240710A: Fermi GBM Final Real-time Localization
  37. EP240708a: NOT optical observations
  38. EP240708a: SVOM/C-GFT optical upper limit
  39. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  40. EP240708a: Optical upper limits with Kinder observations
  41. EP240708a: EP-WXT detection of a fast X-ray transient
  42. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  43. EP240703b: GSP optical upper limit
  44. Fermi Gamma-ray Burst Monitor trigger 741911057/240705933 is not a GRB
  45. GRB 240705A: Fermi GBM Final Real-time Localization
  46. EP240703b: TRT optical upper limits
  47. EP240703a: TRT further optical observation
  48. EP240702a: TRT optical upper limits
  49. Konus-Wind detection of GRB 240627A
  50. IPN triangulation of GRB 240628B (short)
  51. LIGO/Virgo/KAGRA S240705at: Updated Sky localization
  52. EP240703a and EP240703b: Swift/XRT upper limits
  53. LIGO/Virgo/KAGRA S240705at: Identification of a GW compact binary merger candidate
  54. EP240703a: KAIT optical upper limit
  55. EP240703a: BTA observations
  56. EP240703c: Kinder optical follow-up and Swift XRT observations
  57. EP240703a: BOOTES-3 optical upper limit
  58. EP240703a: Liverpool Telescope optical follow-up observations
  59. EP240703a/GRB 240703A: TRT optical candidate likely not real
  60. EP240703a: Kinder optical follow-up observations
  61. EP240703c: EP-WXT detection of an X-ray transient
  62. LIGO/Virgo/KAGRA S240703ad: Updated Sky localization
  63. LIGO/Virgo/KAGRA S240703ad: Identification of a GW compact binary merger candidate
  64. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  65. IPN triangulation of GRB 240627A
  66. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  67. LIGO/Virgo/KAGRA S240422ed: Updated significance estimate
  68. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  69. EP240703b: EP-WXT detection of a fast X-ray transient
  70. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  71. EP240702a: Swift/XRT upper limit
  72. EP240703a: EP-WXT detection of a fast X-ray transient
  73. EP240702a: GSP optical upper limit
  74. The first three GRBs detected by SVOM: GRB 240627B, GRB 240629A and GRB 240702A
  75. GRB 240702A: BALROG localization (Fermi Trigger / GRB 240702885)
  76. Fermi GRB 240702A: Global MASTER-Net observations report
  77. GRB 240702A: Fermi GBM Final Real-time Localization
  78. EP240702a: EP-WXT detection of a fast X-ray transient
  79. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  80. Fermi Gamma-ray Burst Monitor trigger 741448122/240630575 is not a GRB
  81. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  82. Fermi trigger No 741448122: Global MASTER-Net observations report
  83. LIGO/Virgo/KAGRA S240630t: Updated Sky localization
  84. LIGO/Virgo/KAGRA S240629by: Updated Sky localization
  85. LIGO/Virgo/KAGRA S240630t: Identification of a GW compact binary merger candidate
  86. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  87. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  88. Fermi trigger No 741356809: Global MASTER-Net observations report
  89. Fermi GRB 240629A: Global MASTER-Net observations report
  90. Fermi Gamma-ray Burst Monitor trigger 741362867/240629589 is not a GRB
  91. Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
  92. GRB 240629A: BALROG localization (Fermi Trigger 741372837 / GRB 240629704)
  93. GRB 240629A: Fermi GBM Final Real-time Localization
  94. Fermi Gamma-ray Burst Monitor trigger 741356809/240629519 is not a GRB
  95. LIGO/Virgo/KAGRA S240629by: Identification of a GW compact binary merger candidate
  96. Fermi trigger No 741296200: Global MASTER-Net observations report
  97. Fermi trigger No 741251380: Global MASTER-Net observations report
  98. IPN triangulation of GRB 240619C
  99. IceCube-Cascade 240626A: Upper limits from a search for additional neutrino events in IceCube
  100. GRB 240628A: BALROG localization (Fermi Trigger 741288821 / GRB 240628732)

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