Skip to main content
Circulars over Kafka event name backfill. 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"

24618 results found.

  1. GRB 241223A: BALROG localization (Fermi Trigger 756648531 / GRB 241223506)
  2. The EP-WXT trigger 01709129287 is likely a flaring star
  3. EP241217a: Liverpool Telescope optical upper limit
  4. EP241021a: VLA radio detection
  5. GRB 241218A: Mondy AZT-33IK optical upper limit
  6. EP241217a : Leavitt Observatory optical upper limit
  7. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  8. EP241217a: 1.6m Mephisto multi-band optical observations
  9. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  10. GRB 241218A: Swift/UVOT Upper Limits
  11. EP241217a: optical upper limit with the Liverpool Telescope
  12. GRB 241209B: EP-FXT afterglow detection
  13. GRB 241218A: NOT optical upper limits
  14. GRB 241218A: Swift-BAT refined analysis
  15. GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
  16. EP 241217a: NIR detection with P200/WIRC
  17. EP 241217a: Possible J-band detection with WINTER
  18. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  19. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  20. GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
  21. GRB 241217A / EP241217b: NOT optical upper limits
  22. GRB 241218A: REM optical upper limit
  23. GRB 241217A/EP241217b: REM optical/NIR upper limits
  24. EP241217a: REM optical/NIR upper limits
  25. GRB 241217a: Liverpool Telescope optical follow-up
  26. EP241217a: Liverpool Telescope optical follow-up
  27. GRB 241218A: Swift-XRT refined Analysis
  28. EP241217a: NOT optical observations
  29. EP241217a: GROWTH-India Telescope optical observations
  30. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  31. EP241119a: 7DT Optical upper limits
  32. EP241217a: Xinglong optical follow-up observations
  33. EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
  34. GRB 241218A: LCOGT Optical Upper Limit
  35. GRB 241218A: Enhanced Swift-XRT position
  36. GRB 241217A: GMG Optical Upper Limit
  37. GRB 241218A: Swift detection of a burst
  38. GRB 241217A : SVOM/VT optical afterglow detection
  39. GRB 241217A: Swift-XRT afterglow detection
  40. GRB 241217A: LCO optical upper limit
  41. GRB 241217A: GRANDMA/TAROT optical upperlimits
  42. EP241217a: Swift-XRT Detection
  43. EP241217A: Non-detection from Fermi-GBM Observations
  44. GRB 241217A : SVOM/ECLAIRs,GRM,MXT detection of a long burst with a bright X-ray afterglow candidate
  45. EP241217a: Kinder optical follow-up observations
  46. EP241217A: LCO optical observations
  47. EP241217a: Gemini-North detection of the likely optical counterpart
  48. EP241217a: EP detection of an X-ray transient
  49. EP241107a: VLA Radio Observation
  50. GRB 241213A: Swift-BAT refined analysis
  51. GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
  52. GRB 241215A: Mondy AZT-33IK optical observations
  53. GRB 241212A: Swift-XRT observations
  54. GRB 241215A: Nanshan/HMT optical upper limit
  55. GRB 241215A: Montarrenti Observatory optical upper limit
  56. GRB 241215A: GROWTH-India telescope optical upper limit
  57. GRB 241215A: A long GRB detected by INTEGRAL
  58. Integral GRB241215.58: Global MASTER-Net observations report
  59. GRB 241213B: Swift-XRT observations
  60. GRB 241213A: Swift/UVOT Upper Limits
  61. GRB 241213A: Swift-XRT refined Analysis
  62. GRB 241212A: Fermi GBM detection
  63. EP241208a: NOT optical upper limits
  64. GRB 241213A: LCOGT Optical Upper Limits
  65. GRB 241213B: MAXI/GSC detection
  66. EP241213a: EP detection of An X-ray Transient
  67. GRB 241213A: REM optical/NIR upper limits
  68. GRB 241213A: Enhanced Swift-XRT position
  69. GRB241212A: OHP/T193 optical observations
  70. GRB 241213A: SAO RAS optical upper limit
  71. LIGO/Virgo/KAGRA S241210fu: Updated Sky localization
  72. GRB 241213A: Swift detection of a burst
  73. GRB 241212A : SVOM/C-GFT optical upper limit at early phase
  74. GRB 241212A: AstroSat CZTI detection
  75. GRB 241209B: GRANDMA/TRT upper limit
  76. GRB 241207A: TSHAO Zeiss-1000 optical observations
  77. GRB 241212A: SVOM detection of a bright long burst
  78. GRB 241207A: EIRSAT-1 GMOD Detection
  79. LIGO/Virgo/KAGRA S241210cw: Updated Sky localization
  80. LIGO/Virgo/KAGRA S241210d: Updated Sky localization and EM Bright Classification
  81. GRB 241129A: Fermi GBM Observation
  82. GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
  83. GRB 241209D: REM optical/NIR upper limits
  84. GRB 241209B: Swift-XRT afterglow detection
  85. GRB 241209C: Fermi GBM Observation
  86. GRB 241209A: Swift-XRT refined Analysis
  87. LIGO/Virgo/KAGRA S241210fu: Identification of a GW compact binary merger candidate
  88. EP241208a: Optical upper limit with Kinder observations
  89. GRB 241209B: SVOM/VT afterglow detection
  90. LIGO/Virgo/KAGRA S241210cw: Identification of a GW compact binary merger candidate
  91. LIGO/Virgo/KAGRA S241210d: Identification of a GW compact binary merger candidate
  92. GRB 241207B: Fermi GBM Observation
  93. GRB 241209D: Swift-XRT refined Analysis
  94. GRB 241209D: Fermi GBM Observation
  95. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  96. GRB 241209D: COLIBRÍ detection of the afterglow
  97. GRB 241209A: COLIBRÍ Optical Upper Limit
  98. GRB 241209C: Swift/BAT-GUANO localization skymap of a burst
  99. GRB 241209A: GRANDMA/TAROT upper limit
  100. GRB 241209A: REM optical/NIR observations

Advanced

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