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"

32764 results found.

  1. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  2. EP240919a / GRB 240919A: REM optical and NIR upper limits
  3. EP240919a / GRB 240919A: KAIT optical upper limit
  4. EP240918b and EP240918c: Optical upper limits with Kinder observations
  5. GRB 240414A: further radio observations with the VLA
  6. EP240919a: Optical upper limit with Kinder observations
  7. GRB 240919A / EP240919a: SVOM/GRM observation
  8. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  9. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  10. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  11. EP EP240919a: Global MASTER-Net observations report
  12. GRB 240910A: radio detection with the VLA
  13. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  14. EP240919a: NOT and Gemini optical observations
  15. EP240919a: GOTO optical upper limits
  16. EP240919a: JinShan optical upper limits
  17. EP240919a is likely a GRB event (duplicate submission of 37563)
  18. EP240919a is likely a GRB event
  19. LIGO/Virgo/KAGRA S240920bz: Identification of a GW compact binary merger candidate
  20. GRB 240918A and GRB 240918B : INTEGRAL SPI ACS LIGHT CURVE
  21. LIGO/Virgo/KAGRA S240919bn: Updated Sky localization
  22. GRB 240918B: Fermi GBM Detection
  23. LIGO/Virgo/KAGRA S240917cb: Updated Sky localization and EM Bright Classification
  24. LIGO/Virgo/KAGRA S240916ar: Updated Sky localization and EM Bright Classification
  25. EP240918a: EP observation update
  26. GRB 240910A: further Swift observations and confirmation of afterglow
  27. LIGO/Virgo/KAGRA S240919bn: Identification of a GW compact binary merger candidate
  28. EP240918a: Swift-XRT observation
  29. Fermi GRB 240918A: Global MASTER-Net observations report
  30. EP EP240918a: Global MASTER-Net observations report
  31. EP240918a: JinShan optical upper limits
  32. EP240918a: YAHPT Optical Upper Limit
  33. EP240918a: Optical upper limits with Kinder observations
  34. EP240918a: GMG Optical Upper Limit
  35. GRB 240916A: GRBAlpha detection
  36. GRB 240914B: GRBAlpha detection
  37. GRB 240916A: NOT optical observation
  38. GRB 240912A: Swift-BAT refined analysis
  39. IPN triangulation of GRB 240913C / EP 240913a
  40. GRB 240825A: INTEGRAL SPI ACS LIGHT CURVE
  41. GRB 240825A: The nature of the afterglow motivates the search of the associated supernova
  42. GRB 240916A: Fermi GBM Observation
  43. LIGO/Virgo/KAGRA S240917cb: Identification of a GW compact binary merger candidate
  44. GRB 240821A: radio observation with the VLA
  45. GRB 240916A (AT 2024vlp / GOTO24fzn): VLT/X-shooter redshift
  46. GRB 240916A: Swift-XRT afterglow detection
  47. LIGO/Virgo/KAGRA S240916ar: Identification of a GW compact binary merger candidate
  48. GRB 240916A: Swift ToO observations
  49. GRB 240916A: JinShan optical decay in one of the two GOTO candidates
  50. GRB 240916A: GOTO identification of two new optical sources within the GBM localisation region
  51. EP EP240913a: Global MASTER-Net observations report
  52. LIGO/Virgo/KAGRA S240915b: Coverage and upper limits from MAXI/GSC observations
  53. GRB 240916A INTEGRAL SPI ACS LIGHT CURVE
  54. LIGO/Virgo/KAGRA S240915bd: Updated Sky localization
  55. EP240913a: VLT/HAWK-I near-infrared upper limits
  56. LIGO/Virgo/KAGRA S240915bd: Identification of a GW compact binary merger candidate
  57. LIGO/Virgo/KAGRA S240915b: Updated Sky localization and EM Bright Classification
  58. LIGO/Virgo/KAGRA S240915b: Identification of a GW compact binary merger candidate
  59. EP240913a/GRB 240913C: KAIT optical upper limit
  60. EP240913a / GRB 240913C INTEGRAL SPI ACS LIGHT CURVE
  61. GRB 240913C: Fermi GBM detection
  62. GRB 240913C: Joint location by ETJASMIN
  63. GRB 240914B: AstroSat CZTI detection
  64. EP240913A / GRB 240913C: AstroSat CZTI detection
  65. GRB 240914A: SVOM/GRM observation
  66. GRB 240910A: SVOM/VT optical observations
  67. GRB 240914A: Swift ToO observations
  68. EP240913a: NOT optical upper limits
  69. EP240913a: JinShan optical upper limits
  70. EP240913a: ESO-NTT optical observations
  71. GRB 240914A: ESO-NTT optical observations
  72. EP240913a: Swift/XRT detection of an X-ray source within the EP/WXT error circle
  73. GRB 240905E: further NOT optical observations
  74. EP240913a: A GRB Event
  75. GRB 240911A: LCO optical observations
  76. GRB 240911A: JinShan optical upper limits on two Swift/XRT candidates
  77. Fermi Gamma-ray Burst Monitor trigger 747837485/240912526 is not a GRB
  78. GRB 240912A: Swift/UVOT Detection
  79. GRB 240911A: GOTO optical limits on Swift/XRT candidates
  80. GRB 240912A: SVOM/GRM observation
  81. Fermi GRB 240913A: Global MASTER-Net observations report
  82. GRB 240912A: J-band observations with WINTER
  83. GRB 240912A: Fermi GBM Observation
  84. Swift GRB 240912A: Global MASTER-Net observations report
  85. GRB 240912A: LCOGT detection and Legacy Surveys likely host galaxy
  86. GRB 240911A: Tiled Swift observations
  87. GRB 240912A : INTEGRAL SPI ACS LIGHT CURVE
  88. GRB 240912A: NOT optical spectroscopy
  89. GRB 240912A: Redshift from OSIRIS+/GTC
  90. Fast X-ray Transient EP240801a: GMRT radio observations
  91. GRB 240910A: Redshift from OSIRIS+/GTC
  92. GRB 240910A: Fermi GBM Observation
  93. GRB 240910A: NOT optical observations
  94. GRB 240910A: Swift-XRT detection of GOTO24fvl/AT2024vfp
  95. GRB 240910A: JinShan optical observations
  96. GRB 240910A: GOTO candidate optical counterpart
  97. EP240908a: Optical afterglow confirmation
  98. GRB 240710A: SVOM/GRM observation
  99. GRB 240910A: Swift ToO observations
  100. IPN triangulation of GRB 240905B (short)

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