Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! 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"

8474 results found.

  1. LIGO/Virgo/KAGRA S240915b: Updated Sky localization and EM Bright Classification
  2. LIGO/Virgo/KAGRA S240915b: Identification of a GW compact binary merger candidate
  3. EP240913a/GRB 240913C: KAIT optical upper limit
  4. GRB 240914A: Swift ToO observations
  5. GRB 240911A: GOTO optical limits on Swift/XRT candidates
  6. GRB 240912A: LCOGT detection and Legacy Surveys likely host galaxy
  7. GRB 240911A: Tiled Swift observations
  8. GRB 240912A: Swift detection of a burst with an optical counterpart
  9. GRB 240911A : a likely weak GRB detected by SVOM/ECLAIRs
  10. GRB 240910A: Swift-XRT detection of GOTO24fvl/AT2024vfp
  11. GRB 240910A: GOTO candidate optical counterpart
  12. EP240908a: Optical afterglow confirmation
  13. GRB 240910A: Swift ToO observations
  14. GRB 240905E: SVOM/VT optical observations
  15. LIGO/Virgo/KAGRA S240910ci: NED Galaxies in the Localization Volume
  16. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  17. LIGO/Virgo/KAGRA S240910ci: Updated Sky localization and EM Bright Classification
  18. LIGO/Virgo/KAGRA S240910ci: Identification of a GW compact binary merger candidate
  19. EP240908a: Updates on the WXT detection result around the trigger time
  20. LIGO/Virgo/KAGRA S240908bs: Upper limits from Swift/BAT-GUANO
  21. LIGO/Virgo/KAGRA S240907cg: Upper limits from Swift/BAT-GUANO
  22. EP240908a: optical afterglow candidate
  23. GRB 240905B: GOTO optical upper limits
  24. LIGO/Virgo/KAGRA S240908dg: Updated Sky localization
  25. LIGO/Virgo/KAGRA S240908bs: Updated Sky localization
  26. LIGO/Virgo/KAGRA S240908dg: Identification of a GW compact binary merger candidate
  27. LIGO/Virgo/KAGRA S240908bs: Identification of a GW compact binary merger candidate
  28. LIGO/Virgo/KAGRA S240907cg: Updated Sky localization
  29. LIGO/Virgo/KAGRA S240907cg: Identification of a GW compact binary merger candidate
  30. GRB 240905E: GIT optical upper limit
  31. GRB 240905B: Swift ToO observations
  32. GRB 240905E: J-band observations with WINTER
  33. GRB 240905E: CrAO Optical Afterglow observations, possible OT candidate
  34. GRB 240905E: AKO Optical Upper Limit
  35. GRB 240905E: Swift detection of a burst
  36. LIGO/Virgo/KAGRA S240825ar: Upper limits from Swift/BAT-GUANO
  37. LIGO/Virgo/KAGRA S240807h: Upper limits from Swift/BAT-GUANO
  38. LIGO/Virgo/KAGRA S240902bq: Updated Sky localization
  39. LIGO/Virgo/KAGRA S240902bq: Identification of a GW compact binary merger candidate
  40. LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
  41. LIGO/Virgo/KAGRA S240830gn: Updated Sky localization and EM Bright Classification
  42. GRB 240825A: Swift-BAT refined analysis
  43. LIGO/Virgo/KAGRA S240830gn: Identification of a GW compact binary merger candidate
  44. GRB 240828B: SVOM/C-GFT optical upper limit
  45. GRB 240828B: KAIT optical upper limit
  46. GRB 240828A: KAIT Optical Afterglow Candidate
  47. GRB 240828A: Tiled Swift observations
  48. GRB 240825A: Upper limits from a neutrino search with IceCube
  49. GRB 240828B: Swift ToO observations
  50. GRB 240821A: PRIME near-infrared observations
  51. SVOM GRB 240821A: optical afterglow discovery
  52. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  53. LIGO/Virgo/KAGRA S240825ar: Updated Sky localization
  54. LIGO/Virgo/KAGRA S240825ar: Updated Sky localization
  55. GRB 240824B: KAIT optical upper limit
  56. GRB 240824B: NOT optical upper limit
  57. GRB 240825A: Skynet Optical Afterglow observations
  58. GRB 240825A: Swift detection of a burst with a bright optical counterpart
  59. GRB 240824A: SVOM/C-GFT optical upper limit
  60. LIGO/Virgo/KAGRA S240825ar: Identification of a GW compact binary merger candidate
  61. GRB 240824B: Swift ToO observations
  62. GRB240824A: GRANDMA/TAROT-TCA Upper Limit
  63. GRB 240824A: Swift detection of a burst
  64. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  65. EP240820a: PRIME J-band Observations
  66. GRB 240821A: GMG Optical Upper Limit
  67. GRB 240821A: Swift ToO observations
  68. GRB 240821A: EP-FXT follow-up observation and afterglow candidates
  69. GRB 240821A : a likely short GRB detected by SVOM/ECLAIRs
  70. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  71. GRB 240819A: KAIT optical upper limit
  72. EP240816a: PRIME upper limits
  73. GRB 240819A: Swift ToO observations
  74. IceCube-240721A: AT2023qqp and AT2024pge likely unrelated
  75. EP240816b: KAIT optical upper limit
  76. LIGO/Virgo/KAGRA S240813d: Updated Sky localization
  77. LIGO/Virgo/KAGRA S240813d: Identification of a GW compact binary merger candidate
  78. LIGO/Virgo/KAGRA S240813c: Updated Sky localization
  79. LIGO/Virgo/KAGRA S240813c: Identification of a GW compact binary merger candidate
  80. IceCube-240808A: Upper limits from a search for additional neutrino events in IceCube
  81. EP240801a: Assy-Turgen optical observations
  82. GRB 240811A: Swift detection of a burst
  83. LIGO/Virgo/KAGRA S240807h: Updated Sky localization and EM Bright Classification
  84. GRB 240809A: Swift detection of a burst with a bright optical counterpart
  85. IceCube-240808A - IceCube observation of a high-energy neutrino candidate track-like event
  86. S240807h: Identification of a GW compact binary merger candidate
  87. The EP-WXT trigger 01709018832 on August 7th is likely a flaring star
  88. GRB 240626B: VZLUSAT-2 detection
  89. EP240806a: GSP optical counterpart detection
  90. GRB 240805B: Optical detection with 1.6m Mephisto
  91. GRB 240805B: BTA optical afterglow candidate
  92. EP240804a: GSP detects optical candidate counterpart
  93. GRB 240805B: Swift detection of a burst
  94. EP240804a: NOT optical counterpart detection
  95. EP240802a: Montarrenti Observatory optical upper limit
  96. EP240801a: GSP follow-up observations of the candidate counterpart
  97. EP240801a: Kinder follow-up observations of the candidate counterpart
  98. EP240708a: Kinder follow-up observations of the candidate counterpart (duplicate submission of GCN 37002)
  99. GRB 240730A: KAIT Optical Upper Limit
  100. GRB 240730A: Swift detection of a burst

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