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"

19949 results found.

  1. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  2. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  3. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  4. SVOM/GRM observation of GRB 241126B or a short burst from magnetar
  5. IPN triangulation of GRB 241114B
  6. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  7. LIGO/Virgo/KAGRA S241125n: SAGUARO follow-up observations with the MMT
  8. Trigger_18947: Swift ToO observations (retracted)
  9. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  10. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  11. SVOM/GRM detection of a short burst from SGR 1830
  12. GECAM detection of a short burst from SGR 1830
  13. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  14. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  15. EP241125a: EP detection of an X-ray transient
  16. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
  17. LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
  18. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  19. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  20. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  21. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  22. LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event
  23. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  24. Konus-Wind detection of GRB 241117A
  25. IPN triangulation of GRB 241117A
  26. GRB 241025A: VIRT Optical Upper Limit
  27. GRB 241115A: CALET Gamma-Ray Burst Monitor detection
  28. GRB 241115a: PRIME near-infrared upper limits
  29. GRB 241117A: Swift/BAT-GUANO localization skymap of a burst
  30. LIGO/Virgo/KAGRA S241116cq: Upper limits from Swift/BAT-GUANO
  31. GRB 241115B: Fermi GBM Observation
  32. GRB 241115B: Swift/BAT-GUANO localization skymap of a long burst
  33. GRB 241115C: Fermi GBM Observation
  34. GRB 241115A: Swift-XRT afterglow detection
  35. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  36. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  37. EP241113a: Swift XRT weak detection
  38. GRB 241115A: Fermi GBM Observation
  39. GRB 241115A: LCOGT Optical Upper Limits
  40. GRB 241115C: Swift/BAT-GUANO localization skymap of a burst
  41. Swift GRB 241115A: Global MASTER-Net observations report
  42. GRB 241115A: Swift detection of a burst
  43. GRB 241113A: Swift-BAT refined analysis
  44. GRB 241113A: PRIME near-infrared upper limits
  45. GRB 241113A: J-band observations with WINTER
  46. GRB 241113B: Swift-XRT observations
  47. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  48. GRB 241113A: KAIT optical observations
  49. GRB 241113A: Swift-XRT refined Analysis
  50. GRB 241113A: Swift/UVOT Detection
  51. GRB 241113A: REM detection of the optical/NIR afterglow
  52. Konus-Wind detection of GRB 241107A (short/hard)
  53. GRB 241113B: Swift ToO observations
  54. GRB 241113A: LCO optical observations
  55. GRB 241113A: Enhanced Swift-XRT position
  56. GRB241113A: LCOGT (40-cm) optical counterpart detection
  57. GRB 241113A: MASTER010615.66-224018.2 optical counterpart detection
  58. GRB 241113A: Swift detection of a burst with an optical counterpart
  59. Swift GRB241113.33: Global MASTER-Net observations report
  60. SVOM/GRM detection of a short burst from SGR 1E1841-045
  61. GRB 241107A: GROWTH-India telescope optical upper limit
  62. GRB 241112B: Swift-XRT afterglow detection
  63. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  64. GRB 241112B: Swift ToO observations
  65. GRB 241107A: INTEGRAL IBIS localization
  66. IPN triangulation of GRB 241107A (short/hard)
  67. GRB 241025A: VZLUSAT-2 detection
  68. GRB 241108A: Swift-XRT observations
  69. GRB 241108A: Swift ToO observations
  70. GRB 241030A: TESS observations
  71. GRB 241105A: EP-FXT follow-up observations
  72. GRB 241105A: SVOM/GRM observation
  73. GRB 241105a: PRIME near-infrared upper limits
  74. GRB 241105A: Swift/UVOT Detection
  75. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  76. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  77. GRB 241105A: BOOTES-7 optical detection
  78. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  79. GRB 241105A: Swift-XRT afterglow detection
  80. GRB 241104A: Swift-XRT observations
  81. GRB 241105A: Swift ToO observations
  82. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  83. GRB 241104A: Swift ToO observations
  84. GRB 241030A: GRBAlpha detection
  85. EP241103a: GIT optical upper limit
  86. EP241103a: GOTO optical upper limit
  87. EP241103a: Swift XRT detection and improved X-ray position
  88. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  89. GRB 241030A: Rapid release of TESS data.
  90. Swift GRB 241101A: Global MASTER-Net observations report
  91. GRB 241101A: FRAM-ORM optical limit
  92. GRB 241101A: Swift-BAT refined analysis
  93. GRB 241030B: Swift-XRT refined Analysis
  94. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  95. GRB 241101A: Swift detection of a burst
  96. GRB 241030B: Montarrenti Observatory optical upper limit
  97. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  98. GRB 241030A: Fermi GBM Observation
  99. GRB 241030B: LCOGT Optical Upper Limits
  100. GRB 241030B: Swift-BAT refined analysis

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov