Skip to main content
New! BOOM Notices and Schema v7.0.0. 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').
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"

44271 results found.

  1. GRB 240702A: BALROG localization (Fermi Trigger / GRB 240702885)
  2. Fermi GRB 240702A: Global MASTER-Net observations report
  3. GRB 240702A: Fermi GBM Final Real-time Localization
  4. EP240702a: EP-WXT detection of a fast X-ray transient
  5. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  6. Fermi Gamma-ray Burst Monitor trigger 741448122/240630575 is not a GRB
  7. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  8. Fermi trigger No 741448122: Global MASTER-Net observations report
  9. LIGO/Virgo/KAGRA S240630t: Updated Sky localization
  10. LIGO/Virgo/KAGRA S240629by: Updated Sky localization
  11. LIGO/Virgo/KAGRA S240630t: Identification of a GW compact binary merger candidate
  12. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  13. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  14. Fermi trigger No 741356809: Global MASTER-Net observations report
  15. Fermi GRB 240629A: Global MASTER-Net observations report
  16. Fermi Gamma-ray Burst Monitor trigger 741362867/240629589 is not a GRB
  17. Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
  18. GRB 240629A: BALROG localization (Fermi Trigger 741372837 / GRB 240629704)
  19. GRB 240629A: Fermi GBM Final Real-time Localization
  20. Fermi Gamma-ray Burst Monitor trigger 741356809/240629519 is not a GRB
  21. LIGO/Virgo/KAGRA S240629by: Identification of a GW compact binary merger candidate
  22. Fermi trigger No 741296200: Global MASTER-Net observations report
  23. Fermi trigger No 741251380: Global MASTER-Net observations report
  24. IPN triangulation of GRB 240619C
  25. IceCube-Cascade 240626A: Upper limits from a search for additional neutrino events in IceCube
  26. GRB 240628A: BALROG localization (Fermi Trigger 741288821 / GRB 240628732)
  27. GRB 240627A: NuSTAR Detection of the long GRB
  28. GRB 240615A: SAI CMO J- band observations
  29. GRB 240627A: AstroSat CZTI detection
  30. Fermi trigger No 741211696: Global MASTER-Net observations report
  31. EP240626a: Montarrenti Observatory optical upper limit
  32. EP240626a: KAIT optical upper limit
  33. LIGO/Virgo/KAGRA S240627by: Identification of a GW compact binary merger candidate
  34. EP240625a: GRANDMA Optical Upper Limits
  35. EP240626a: EP-FXT detection of the X-ray emission
  36. GRB 240624A: Swift-BAT refined analysis
  37. Konus-Wind detection of GRB 240619A
  38. EP240626a: BOOTES-7 optical upper limit
  39. EP240626a: EP-WXT detection of a fast X-ray transient
  40. Fermi GRB 240625B: Global MASTER-Net observations report
  41. GRB 240624B: CALET Gamma-Ray Burst Monitor detection
  42. GRB 240625B: Fermi GBM Final Real-time Localization
  43. GRB 240625A: Fermi GBM Observation
  44. EP240625a: NOT optical counterpart candidate
  45. EP240625a: EP-FXT detection of the X-ray emission
  46. GRB 240624B: GRBAlpha detection
  47. GRB 240625A: Fermi GBM Final Real-time Localization
  48. EP240625a: EP-WXT detection of a fast X-ray transient
  49. GRB240624A: Fermi GBM Observation
  50. LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
  51. LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
  52. LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
  53. Swift GRB 240624A: Global MASTER-Net observations report
  54. GRB240615A: Gemini-North observations of the BAT and XRT positions
  55. Fermi GRB 240624A: Global MASTER-Net observations report
  56. GRB 240624B: Fermi GBM Final Real-time Localization
  57. Fermi trigger No 740949590: Global MASTER-Net observations report
  58. LIGO/Virgo/KAGRA S240624cd: Retraction of GW unmodeled transient candidate
  59. GRB240615A: Gemini-North observations of the BAT and XRT positions
  60. GRB 240624A: Fermi GBM Final Real-time Localization
  61. GRB 240619A: detection of a radio counterpart with AMI-LA
  62. GRB 240624A: Swift detection of a burst
  63. LIGO/Virgo/KAGRA S240623dg: Retraction of GW compact binary merger candidate
  64. EP240618a: NOT further optical observations
  65. GRB 240619A: J-band detection with WINTER (duplicate submission of GCN 36739)
  66. GRB 240619A: J-band detection with WINTER
  67. LIGO/Virgo/KAGRA S240622h: Updated Sky localization and Source Classification
  68. Fermi trigger No 740744838: Global MASTER-Net observations report
  69. EP240618a: NOT optical counterpart candidate
  70. LIGO/Virgo/KAGRA S240621em: Updated Sky localization and Source Classification
  71. GRB 240529A: JinShan optical observations
  72. LIGO/Virgo/KAGRA S240621dy: Updated Sky localization and Source Classification
  73. LIGO/Virgo/KAGRA S240621eb: Updated Sky localization and Source Classification
  74. EP240618a: GSP optical upper limit
  75. LIGO/Virgo/KAGRA S240622h: Identification of a GW compact binary merger candidate
  76. LIGO/Virgo/KAGRA S240621em: Identification of a GW compact binary merger candidate
  77. LIGO/Virgo/KAGRA S240621eb: Identification of a GW compact binary merger candidate
  78. LIGO/Virgo/KAGRA S240621dy: Identification of a GW compact binary merger candidate
  79. IPN triangulation of GRB 240615A (short)
  80. X-ray transient EP240618a: Fermi/GBM non-detection
  81. GRB 240619A: GRBAlpha detection
  82. EP240618a: Swift/XRT upper limit
  83. EP240617a: tentative Swift/XRT detection of the afterglow
  84. GRB 240619A: Swift-XRT probable afterglow detection
  85. GRB 240619A: Swift ToO observations
  86. GRB 240619A: CALET Gamma-Ray Burst Monitor detection
  87. GRB 240619C: NuSTAR automated detection of the GRB
  88. GRB 240619A: Fermi GBM Observation
  89. Fermi GBM Sub-Threshold Detection of GRB 240619C
  90. GRB 240619A: GOTO candidate optical afterglow
  91. EP240618a: Abastumani optical observationsEP240618a
  92. GRB 240615A: NOT optical observations
  93. EP240618a: GRANDMA Optical Upper Limits
  94. GRB 240619C: AstroSat CZTI detection
  95. EP240618a: TRT optical upper limit
  96. Fermi trigger No 740474239: Global MASTER-Net observations report
  97. Fermi GRB 240619A: Global MASTER-Net observations report
  98. EP240617a: STEP/T80S optical limits
  99. GRB 240615A: possible transient detection from Wendelstein observations
  100. LIGO/Virgo S240615dg: GRANDMA/FRAM-CTA-N Observations

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