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"

31632 results found.

  1. LIGO/Virgo/KAGRA S240703ad: Identification of a GW compact binary merger candidate
  2. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  3. IPN triangulation of GRB 240627A
  4. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  5. LIGO/Virgo/KAGRA S240422ed: Updated significance estimate
  6. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  7. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  8. EP240702a: Swift/XRT upper limit
  9. EP240702a: GSP optical upper limit
  10. Fermi GRB 240702A: Global MASTER-Net observations report
  11. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  12. LIGO/Virgo/KAGRA S240630t: Updated Sky localization
  13. LIGO/Virgo/KAGRA S240629by: Updated Sky localization
  14. LIGO/Virgo/KAGRA S240630t: Identification of a GW compact binary merger candidate
  15. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  16. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  17. Fermi GRB 240629A: Global MASTER-Net observations report
  18. Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
  19. LIGO/Virgo/KAGRA S240629by: Identification of a GW compact binary merger candidate
  20. IPN triangulation of GRB 240619C
  21. GRB 240627A: NuSTAR Detection of the long GRB
  22. GRB 240615A: SAI CMO J- band observations
  23. EP240626a: Montarrenti Observatory optical upper limit
  24. LIGO/Virgo/KAGRA S240627by: Identification of a GW compact binary merger candidate
  25. EP240625a: GRANDMA Optical Upper Limits
  26. EP240626a: EP-FXT detection of the X-ray emission
  27. GRB 240624A: Swift-BAT refined analysis
  28. Konus-Wind detection of GRB 240619A
  29. Fermi GRB 240625B: Global MASTER-Net observations report
  30. GRB 240624B: CALET Gamma-Ray Burst Monitor detection
  31. GRB 240625A: Fermi GBM Observation
  32. EP240625a: NOT optical counterpart candidate
  33. EP240625a: EP-FXT detection of the X-ray emission
  34. GRB 240624B: GRBAlpha detection
  35. GRB240624A: Fermi GBM Observation
  36. Swift GRB 240624A: Global MASTER-Net observations report
  37. GRB240615A: Gemini-North observations of the BAT and XRT positions
  38. Fermi GRB 240624A: Global MASTER-Net observations report
  39. GRB240615A: Gemini-North observations of the BAT and XRT positions
  40. GRB 240619A: detection of a radio counterpart with AMI-LA
  41. EP240618a: NOT further optical observations
  42. GRB 240619A: J-band detection with WINTER (duplicate submission of GCN 36739)
  43. GRB 240619A: J-band detection with WINTER
  44. LIGO/Virgo/KAGRA S240622h: Updated Sky localization and Source Classification
  45. EP240618a: NOT optical counterpart candidate
  46. LIGO/Virgo/KAGRA S240621em: Updated Sky localization and Source Classification
  47. GRB 240529A: JinShan optical observations
  48. LIGO/Virgo/KAGRA S240621dy: Updated Sky localization and Source Classification
  49. LIGO/Virgo/KAGRA S240621eb: Updated Sky localization and Source Classification
  50. EP240618a: GSP optical upper limit
  51. LIGO/Virgo/KAGRA S240622h: Identification of a GW compact binary merger candidate
  52. LIGO/Virgo/KAGRA S240621em: Identification of a GW compact binary merger candidate
  53. LIGO/Virgo/KAGRA S240621eb: Identification of a GW compact binary merger candidate
  54. LIGO/Virgo/KAGRA S240621dy: Identification of a GW compact binary merger candidate
  55. IPN triangulation of GRB 240615A (short)
  56. X-ray transient EP240618a: Fermi/GBM non-detection
  57. GRB 240619A: GRBAlpha detection
  58. EP240618a: Swift/XRT upper limit
  59. EP240617a: tentative Swift/XRT detection of the afterglow
  60. GRB 240619A: Swift-XRT probable afterglow detection
  61. GRB 240619A: Swift ToO observations
  62. GRB 240619A: CALET Gamma-Ray Burst Monitor detection
  63. GRB 240619C: NuSTAR automated detection of the GRB
  64. GRB 240619A: Fermi GBM Observation
  65. Fermi GBM Sub-Threshold Detection of GRB 240619C
  66. GRB 240619A: GOTO candidate optical afterglow
  67. EP240618a: Abastumani optical observationsEP240618a
  68. GRB 240615A: NOT optical observations
  69. EP240618a: GRANDMA Optical Upper Limits
  70. EP240618a: TRT optical upper limit
  71. Fermi GRB 240619A: Global MASTER-Net observations report
  72. EP240617a: STEP/T80S optical limits
  73. GRB 240615A: possible transient detection from Wendelstein observations
  74. LIGO/Virgo S240615dg: GRANDMA/FRAM-CTA-N Observations
  75. LIGO/Virgo/KAGRA S240615dg: Updated Sky localization
  76. LIGO/Virgo/KAGRA S240618ah: Updated Sky localization
  77. EP240618a: OHP/T193 MISTRAL i' and Y band upper limits
  78. GRB240615A: 1.3m DFOT optical upper limit
  79. EP240617a is likely a GRB event
  80. LIGO/Virgo/KAGRA S240618ah: Identification of a GW compact binary merger candidate
  81. GRB 240615A: J-band upper limits from WINTER
  82. GRB 240615A: Fermi GBM Observation
  83. LIGO/Virgo/KAGRA S240615ea: Updated Sky localization
  84. GRB 240615A: GECAM detection
  85. X-ray transient EP240414a: Chandra late time observation
  86. GRB 240615A: FLWO-1.2m optical upper limits
  87. Fermi GRB 240616A: Global MASTER-Net observations report
  88. Konus-Wind detection of GRB 240615A (short/hard)
  89. GRB 240615A: GOTO optical upper limits
  90. GRB 240615A: Swift ToO observations
  91. GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
  92. LIGO/Virgo/KAGRA S240615ea: Identification of a GW compact binary merger candidate
  93. LIGO/Virgo/KAGRA S240615dg: Identification of a GW compact binary merger candidate
  94. GRB 240603A: VZLUSAT-2 detection
  95. GRB 240612A: GRBAlpha detection
  96. Fermi GRB 240612B: Global MASTER-Net observations report
  97. Fermi GRB 240612A: Global MASTER-Net observations report
  98. GRB 240607A: GECAM detection of a bright long burst
  99. Fermi GRB 240611A: Global MASTER-Net observations report
  100. Konus-Wind detection of GRB 240607A

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