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"

28269 results found.

  1. GRANDMA/OPD observations of GRB250215A
  2. GRB 250215A / EP250215a: LCO detection of the afterglow
  3. GRB 250215A: Swift/UVOT Upper Limits
  4. GRB 250215A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  5. GRB 250215A: Fermi GBM Observation
  6. GRB 250215A/EP250215a: 1.6m Mephisto optical observation report
  7. GRB 250213A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  8. GRB 250215A: Swift-XRT refined Analysis
  9. GRB 250215A: SVOM/GRM observation
  10. EP250215a / GRB 250215A (potentially): NOT likely optical counterpart
  11. EP250215a: EP-WXT detection and FXT follow-up observation of an X-ray transient
  12. EP250207b: Xinglong optical upper limit
  13. EP250212a: Xinglong optical upper limit
  14. LIGO/Virgo/KAGRA S250206dm: DECam GW-MMADS candidates
  15. EP250212a: Global MASTER-Net observations report
  16. GRB 250205A: VIRT Optical Upper Limit
  17. GRB 250205A: Leavitt Observatory optical upper limit
  18. EP250207B: Chandra localization of the X-ray counterpart
  19. EP250212a: Liverpool Telescope optical upper limits
  20. GRB250101A: Radio upper limits from GMRT observations
  21. EP trigger 10202399251 (possibly EP250212a): NOT J-band upper limit
  22. EP250207B: GTC z-band Observations
  23. Fermi GRB 250212A: Global MASTER-Net observations report
  24. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Follow-up of AT2025ber
  25. GRB 250205A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  26. Fermi trigger No 760945500: Global MASTER-Net observations report
  27. EP250207b: NOT optical counterpart candidate
  28. GRB 250211B: A long GRB detected by INTEGRAL
  29. LIGO/Virgo/KAGRA S250206dm: GECKO Continued Observaiton with 7DT
  30. LIGO/Virgo/KAGRA S250206dm: AT 2025bbo observations with WFST
  31. LIGO/Virgo/KAGRA S250211be: Updated Sky localization
  32. GRB 250207A: Fermi GBM Observation
  33. GRB 250206A: Fermi GBM Observation
  34. GRB 250205A / EP250205A: radio detection with the VLA
  35. EP250207b: Tentative z-band brightening source
  36. LIGO/Virgo/KAGRA S250206dm: Kinder confirmation of a possible artefact in AT 2025bbo
  37. Konus-Wind detection of GRB 250206A
  38. GRB 250210A: SVOM/GRM observation of a long burst
  39. EP250207b: Liverpool Telescope possible optical counterpart
  40. LIGO/Virgo/KAGRA S250211be: Identification of a GW compact binary merger candidate
  41. LIGO/Virgo/KAGRA S250211aa: Updated Sky localization and EM Bright Classification
  42. LIGO/Virgo/KAGRA S250211aa: Identification of a GW compact binary merger candidate
  43. GRB 250207A: Skynet optical afterglow observations
  44. GRB 241128A: VIRT Optical Upper Limit
  45. EP250207b: Gemini GMOS-N z-band observations
  46. EP250207A: Upper limits from Fermi-GBM Observations
  47. EP250207b: a new X-ray transient detected by Einstein Probe
  48. GRB 250209A: MAXI/GSC detection (possible detection of an X-ray flare from 1RXS J145110.3+310648)
  49. LIGO/Virgo/KAGRA S250206dm: Upper limits from GECAM Observations
  50. IceCube-250207A: Upper limits from a search for additional neutrino events in IceCube
  51. LIGO/Virgo/KAGRA S250206dm: Global MASTER-Net observations report
  52. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of AT2025bbo and Galaxies in the Localization Volume
  53. LIGO/Virgo/KAGRA S250206dm: Observations from WINTER
  54. LIGO/Virgo/KAGRA S250206dm: Optical observations of candidate AT 2025bbo with Kinder
  55. Fermi-LAT Gamma-ray Observations of IceCube-250207A
  56. GRB 250207A: 1.3m DFOT Optical observations
  57. LIGO/Virgo/KAGRA S250206dm: WFST follow-up observations
  58. GRB 250206A: Swift-XRT observations
  59. GRB 250129A: GRANDMA Continued Afterglow Detection
  60. GRB 250207A: Swift-BAT refined analysis
  61. LIGO/Virgo/KAGRA S250206dm: further Pan-STARRS observations and one candidate AT2025bbo
  62. LIGO/Virgo/KAGRA S250207bg: Updated NED Galaxies in the Localization Volume
  63. LIGO/Virgo/KAGRA S250207bg: Updated Sky localization
  64. LIGO/Virgo/KAGRA S250206dm: GECKO Observation with 7DT and KMTNet
  65. GRB 250205A: 1.3m DFOT optical upper limit
  66. LIGO/Virgo/KAGRA S250118az: Updated Sky localization
  67. LIGO/Virgo/KAGRA S250208ad: Updated Sky localization
  68. GRB 250206A: EIRSAT-1 GMOD Detection
  69. LIGO/Virgo/KAGRA S250206dm: (Update-7) NED Galaxies in the Localization Volume
  70. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Observations
  71. GRB 250207B: Swift-XRT observations
  72. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  73. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the DDOTI optical candidates
  74. LIGO/Virgo/KAGRA S250208ad: Identification of a GW compact binary merger candidate
  75. LIGO/Virgo/KAGRA S250206dm: MMT galaxy targeted observations
  76. GRB 250207A: Swift-XRT refined Analysis
  77. LIGO/Virgo/KAGRA S250206dm: FRB 20250206A & "Time Machine" Effect.
  78. EP trigger 01709131361 (possible EP250207a): NOT optical observations and flaring star
  79. GRB 250207A: Enhanced Swift-XRT position
  80. CHIME/FRB source FRB 20250206A detected less than 1 minute after LIGO-Virgo-Kagra (LVK) S250206dm, however the probability of spatial coincidence is order 0.1%
  81. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  82. GRB 250207A: REM IR afterglow detection
  83. LIGO/Virgo/KAGRA S250206dm: ATLAS observations of the skymap
  84. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS survey of the skymap for optical transients
  85. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limits
  86. LIGO/Virgo/KAGRA S250207bg: NED Galaxies in the Localization Volume
  87. IGO/Virgo/KAGRA S250206dm: Virtual Telescope Project upper limit for the Neutrino IceCube Candidate
  88. GRB 250207A: REM optical afterglow detection
  89. LIGO/Virgo/KAGRA S250207bg: Identification of a GW compact binary merger candidate
  90. LIGO/Virgo/KAGRA S250206dm:GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  91. GRB 250207A: Swift/UVOT Detection
  92. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limit for the Neutrino IceCube Candidate
  93. LIGO/Virgo/KAGRA S250206dm: GOTO observations of optical candidates AT 2025azn and AT 2025azm
  94. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS observations of AT2025azm and AT2025azn
  95. LIGO/Virgo/KAGRA S250206dm: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  96. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the AT 2025azn Optical Candidate
  97. GRB 250129A: Continued AbAO and Mondy optical observations
  98. LIGO/Virgo/KAGRA S250206dm: SAGUARO Detection of Two Potential Optical Counterparts
  99. GRB 250207B: MAXI/GSC detection
  100. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection

Advanced

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