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"

21943 results found.

  1. GRB 240916A: GOTO identification of two new optical sources within the GBM localisation region
  2. EP240913a: VLT/HAWK-I near-infrared upper limits
  3. LIGO/Virgo/KAGRA S240915bd: Identification of a GW compact binary merger candidate
  4. LIGO/Virgo/KAGRA S240915b: Updated Sky localization and EM Bright Classification
  5. LIGO/Virgo/KAGRA S240915b: Identification of a GW compact binary merger candidate
  6. GRB 240914A: Swift-XRT observations
  7. GRB 240914B: AstroSat CZTI detection
  8. EP240913A / GRB 240913C: AstroSat CZTI detection
  9. GRB 240910A: SVOM/VT optical observations
  10. EP240913a: NOT optical upper limits
  11. EP240913a: JinShan optical upper limits
  12. EP240913a: ESO-NTT optical observations
  13. GRB 240914A: ESO-NTT optical observations
  14. GRB 240905E: further NOT optical observations
  15. EP240913a: A GRB Event
  16. EP240913a: EP-WXT detection of a fast X-ray transient
  17. GRB 240911A: LCO optical observations
  18. GRB 240911A: JinShan optical upper limits on two Swift/XRT candidates
  19. GRB 240912A: Swift/UVOT Detection
  20. GRB 240911A: GOTO optical limits on Swift/XRT candidates
  21. GRB 240912A: J-band observations with WINTER
  22. GRB 240912A: Swift-XRT refined Analysis
  23. GRB 240912A: LCOGT detection and Legacy Surveys likely host galaxy
  24. GRB 240912A: Enhanced Swift-XRT position
  25. GRB 240912A: Redshift from OSIRIS+/GTC
  26. Fast X-ray Transient EP240801a: GMRT radio observations
  27. GRB 240912A: Swift detection of a burst with an optical counterpart
  28. GRB 240910A: JinShan optical observations
  29. GRB 240910A: GOTO candidate optical counterpart
  30. IPN triangulation of GRB 240905B (short)
  31. GRB 240825A: 7DT Optical Upper Limit
  32. GRB 240905E: SVOM/VT optical observations
  33. GRB 240910A: GRBAlpha detection
  34. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  35. LIGO/Virgo/KAGRA S240910ci: Updated Sky localization and EM Bright Classification
  36. LIGO/Virgo/KAGRA S240910ci: Identification of a GW compact binary merger candidate
  37. GRB 240910A: SVOM/GRM observation
  38. EP240908a: Mondy and AbAO follow-up observations
  39. LIGO/Virgo/KAGRA S240908bs: Upper limits from Swift/BAT-GUANO
  40. LIGO/Virgo/KAGRA S240907cg: Upper limits from Swift/BAT-GUANO
  41. EP240908a: TRT optical upper limit
  42. GRB 240905B: GOTO optical upper limits
  43. EP240908a: EP detection of a fast X-ray transient
  44. LIGO/Virgo/KAGRA S240908dg: Identification of a GW compact binary merger candidate
  45. LIGO/Virgo/KAGRA S240908bs: Identification of a GW compact binary merger candidate
  46. LIGO/Virgo/KAGRA S240907cg: Identification of a GW compact binary merger candidate
  47. GRB 240905E: GIT optical upper limit
  48. GRB 240905B: Swift-XRT observations
  49. GRB 240905E: Gaoyazi/GOT optical upper limits
  50. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  51. GRB 240905E: J-band observations with WINTER
  52. GRB 240905E: CrAO Optical Afterglow observations, possible OT candidate
  53. GRB 240905E: AKO Optical Upper Limit
  54. GRB 240905E: SVOM/C-GFT optical upper limit
  55. GRB 240905E: OHP/MISTRAL T193 optical upper limit
  56. Fermi GRB 240905D: Global MASTER-Net observations report
  57. GRB 240905E: NOT optical upper limits
  58. GRB 240905E: REM optical/NIR upper limits
  59. GRB 240905E: LCOGT Optical Upper Limit
  60. GRB 240905E: Swift/UVOT Upper Limits
  61. GRB 240905E: SAO RAS optical upper limit
  62. GRB 240905E: Nanshan/HMT optical upper limit
  63. GRB 240905E: Swift detection of a burst
  64. GRB 240819A: Optical upper limits from TESS
  65. GRB 240905D: Fermi GBM Final Real-time Localization
  66. GRB 240905C: Fermi GBM Final Real-time Localization
  67. GRB 240905B: Fermi GBM Final Real-time Localization
  68. GRB 240905A: Fermi GBM Final Real-time Localization
  69. LIGO/Virgo/KAGRA S240825ar: Upper limits from Swift/BAT-GUANO
  70. LIGO/Virgo/KAGRA S240807h: Upper limits from Swift/BAT-GUANO
  71. LIGO/Virgo/KAGRA S240902bq: Identification of a GW compact binary merger candidate
  72. GRB 240825A: MeerLICHT afterglow detection
  73. GRB 240828A: SAO RAS AS-500(2) optical observations
  74. GRB 240825A: TSHAO Optical Upper Limit
  75. GRB 240829B: GRBAlpha detection
  76. GRB240828B: REM optical/NIR upper limits
  77. GRB 240828B: AbAO optical upper limit
  78. GRB 240825A: SOAR observations
  79. GRB 240828B: Mephisto optical upper limit
  80. GRB 240828B: GRANDMA Optical Upper Limit
  81. LIGO/Virgo/KAGRA S240830gn: Updated Sky localization and EM Bright Classification
  82. LIGO/Virgo/KAGRA S240830gn: Identification of a GW compact binary merger candidate
  83. GRB 240828B: J-band upper limit from WINTER
  84. GRB 240828B: GMG Optical Upper Limit
  85. GRB 240828B: SVOM/C-GFT optical upper limit
  86. GRB 240828B: SAO RAS optical upper limit
  87. GRB 240828A: SAO RAS optical observations
  88. GRB 240828A: KAIT Optical Afterglow Candidate
  89. GRB 240825A: SVOM/VT optical detection
  90. GRB 240825A: further SAO RAS optical observations
  91. GRB 240825A: iTelescope optical observations
  92. GRB 240828B: Swift-XRT afterglow detection
  93. GRB 240828A: AstroSat CZTI detection of a long burst
  94. Fermi GRB 240828A: Bassano Bresciano Observatory upper limit
  95. GRB 240825A: Upper limits from a neutrino search with IceCube
  96. GRB 240819A as a likely X-Ray Flash
  97. GRB 240821A: PRIME near-infrared observations
  98. GRB 240828B : Detection of a possible very soft X-ray transient by SVOM/ECLAIRs
  99. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  100. GRB 240825A: SAO RAS optical 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