Skip to main content
JSON Notices via Email, Kafka Cron Jobs, Submitter Profile, GCN is Hiring. 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"

32720 results found.

  1. GRB 241217A: LCO optical upper limit
  2. GRB 241217A: GRANDMA/TAROT optical upperlimits
  3. EP241217a: Swift-XRT Detection
  4. EP241217A: Non-detection from Fermi-GBM Observations
  5. EP241217a: Gemini-North spectroscopic redshift z = 4.59
  6. EP241217a: Kinder optical follow-up observations
  7. GRB 241214A: GRBAlpha detection
  8. GRB 241213A (EP241213a): GRBAlpha detection
  9. GRB 241209D: GRBAlpha detection
  10. EP241217A: LCO optical observations
  11. EP241217a: Gemini-North detection of the likely optical counterpart
  12. EP241107a: VLA Radio Observation
  13. GRB 241213A: Swift-BAT refined analysis
  14. GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
  15. Konus-Wind detection of GRB 241213A (EP 241213a)
  16. GRB 241215A: Mondy AZT-33IK optical observations
  17. GRB 241215A: Nanshan/HMT optical upper limit
  18. GRB 241215A: Montarrenti Observatory optical upper limit
  19. GRB 241215A: GROWTH-India telescope optical upper limit
  20. GRB 241209D: CALET Gamma-Ray Burst Monitor detection
  21. GRB 241209B: SVOM/VT optical continuous fading
  22. GRB 241213A: SVOM/VT optical candidate
  23. GRB 241213B: Tiled Swift observations
  24. GRB 241213A: Swift/UVOT Upper Limits
  25. GRB 241213B: CALET Gamma-Ray Burst Monitor detection
  26. GRB 241212A: Fermi GBM detection
  27. EP241208a: NOT optical upper limits
  28. GRB 241212A: Swift ToO observations
  29. GRB 241213A: LCOGT Optical Upper Limits
  30. EP 241208A : Detection of a long soft transient by SVOM/ECLAIRs
  31. EP241213a/GRB241213a: Likely joint detection and INTEGRAL/SPI-ACS counterpart
  32. GRB 241213A: REM optical/NIR upper limits
  33. GRB241212A: OHP/T193 optical observations
  34. GRB 241213A: SAO RAS optical upper limit
  35. LIGO/Virgo/KAGRA S241210fu: Updated Sky localization
  36. Swift GRB 241213A: Global MASTER-Net observations report
  37. GRB 241212A : SVOM/C-GFT optical upper limit at early phase
  38. GRB 241212A : SVOM/VT bright optical afterglow
  39. GRB 241212A: AstroSat CZTI detection
  40. GRB 241209B: GRANDMA/TRT upper limit
  41. GRB 241207A: TSHAO Zeiss-1000 optical observations
  42. GRB 241212A: SVOM detection of a bright long burst
  43. GRB 241209B: Mondy AZT-33IK and AbAO AS-32 optical observations
  44. GRB 241209A: Chandra X-ray Detection
  45. Konus-Wind detection of GRB 241209B
  46. GRB 241207A: EIRSAT-1 GMOD Detection
  47. GRB 241209A: Redshift of the likely host galaxy z = 0.784 from OSIRIS+/GTC
  48. GRB 241209B: GRBAlpha detection
  49. GRB 241206C: GRBAlpha detection
  50. LIGO/Virgo/KAGRA S241210cw: Updated Sky localization
  51. LIGO/Virgo/KAGRA S241210d: Updated Sky localization and EM Bright Classification
  52. GRB 241129A: Fermi GBM Observation
  53. GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
  54. GRB 241209D: REM optical/NIR upper limits
  55. Konus-Wind detection of GRB 241209D
  56. GRB 241209B: Swift-XRT afterglow detection
  57. GRB 241209C: Fermi GBM Observation
  58. LIGO/Virgo/KAGRA S241210fu: Identification of a GW compact binary merger candidate
  59. EP241208a: Optical upper limit with Kinder observations
  60. GRB 241128A: CrAO ZTSh and Mondy AZT-33IK optical observations
  61. GRB 241209D: AstroSat CZTI detection
  62. GRB 241209A: EP-FXT follow-up observations
  63. GRB 241209B: SVOM/VT afterglow detection
  64. LIGO/Virgo/KAGRA S241210cw: Identification of a GW compact binary merger candidate
  65. EP241208a: Global MASTER-Net observations report
  66. EP241208a: EP-FXT follow-up observations
  67. LIGO/Virgo/KAGRA S241210d: Identification of a GW compact binary merger candidate
  68. GRB 241207B: Fermi GBM Observation
  69. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  70. GRB 241209D: Fermi GBM Observation
  71. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  72. GRB 241209D: COLIBRÍ detection of the afterglow
  73. GRB 241209A: COLIBRÍ Optical Upper Limit
  74. Fermi GRB 241209D: Global MASTER-Net observations report
  75. GRB 241209A: Fermi GBM Observation
  76. GRB 241209C: Swift/BAT-GUANO localization skymap of a burst
  77. GRB 241209A: GRANDMA/TAROT upper limit
  78. GRB 241209B: BOOTES-5 optical upper limit
  79. Swift GRB 241209D: Global MASTER-Net observations report
  80. Fermi GRB 241209C: Global MASTER-Net observations report
  81. Fermi GRB 241209E: Global MASTER-Net observations report
  82. GRB 241209B: Swift ToO observations
  83. LIGO/Virgo/KAGRA S241102br: continued GRAWITA observations and detection of an optical transient (AT2024adip)
  84. GRB 241209A: REM optical/NIR observations
  85. GRB 241209C: AstroSat CZTI detection
  86. GRB 241209A: VLT/X-shooter spectroscopy
  87. GRB 241114B: cubesat Avion detection
  88. GRB 241209A: VLT optical observations
  89. Fermi GRB 241209A: Global MASTER-Net observations report
  90. GRB 241209A: GOTO optical upper limits
  91. Fermi GRB 241207B: Global MASTER-Net observations report
  92. GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
  93. GRB 241201A: AstroSat CZTI detection
  94. GRB 241206A: DDOTI Upper Limit on the Afterglow
  95. AT2024adec: X-ray Upper Limits from EP-FXT Observation
  96. GRB 241207C: MASTER optical observations
  97. GRB 241207C: Tiled Swift observations
  98. Fermi GRB 241207A: Global MASTER-Net observations report
  99. EP241206a: Global MASTER-Net observations report
  100. GRB 241206A: Fermi GBM observation

Advanced

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