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"

16111 results found.

  1. GRB 250205A / EP250205A: radio detection with the VLA
  2. LIGO/Virgo/KAGRA S250206dm: Kinder confirmation of a possible artefact in AT 2025bbo
  3. GRB 250210A: SVOM/GRM observation of a long burst
  4. EP250207b: Liverpool Telescope possible optical counterpart
  5. Gemini-South spectroscopic redshift of EP250207b host galaxy candidate (z=0.082)
  6. GRB 250207A: Skynet optical afterglow observations
  7. GRB 241128A: VIRT Optical Upper Limit
  8. EP250207b: Gemini GMOS-N z-band observations
  9. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of AT2025bbo and Galaxies in the Localization Volume
  10. LIGO/Virgo/KAGRA S250206dm: Optical observations of candidate AT 2025bbo with Kinder
  11. GRB 250207A: 1.3m DFOT Optical observations
  12. LIGO/Virgo/KAGRA S250206dm: FRB 20250206A BOOTES-5 and 2.2m CAHA optical upper limits
  13. GRB 250129A: GRANDMA Continued Afterglow Detection
  14. LIGO/Virgo/KAGRA S250206dm: GECKO Observation with 7DT and KMTNet
  15. GRB 250205A: 1.3m DFOT optical upper limit
  16. LIGO/Virgo/KAGRA S250206dm: Spectroscopic Classification of AT2025bay and AT2025baz with Keck I/LRIS
  17. LIGO/Virgo/KAGRA S250206dm: Candidates from the Zwicky Transient Facility
  18. LIGO/Virgo/KAGRA S250206dm: ePESSTO+ classification of AT2025bar
  19. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the DDOTI optical candidates
  20. LIGO/Virgo/KAGRA S250206dm: MMT galaxy targeted observations
  21. EP-WXT trigger 01709131361: correction to GCN 39214
  22. EP trigger 01709131361 (possible EP250207a): NOT optical observations and flaring star
  23. LIGO/Virgo/KAGRA S250206dm: GOTO counterpart search update - AT2025bar
  24. EP-WXT trigger 01709131361 / LIGO/Virgo/KAGRA S250206dm: FTW optical and NIR observations
  25. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  26. GRB 250207A: REM IR afterglow detection
  27. LIGO/Virgo/KAGRA S250206dm: ATLAS observations of the skymap
  28. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS survey of the skymap for optical transients
  29. GRB 250207A: FRAM-Auger optical detection
  30. IGO/Virgo/KAGRA S250206dm: Virtual Telescope Project upper limit for the Neutrino IceCube Candidate
  31. GRB 250207A: REM optical afterglow detection
  32. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limit for the Neutrino IceCube Candidate
  33. LIGO/Virgo/KAGRA S250206dm: GOTO observations of optical candidates AT 2025azn and AT 2025azm
  34. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS observations of AT2025azm and AT2025azn
  35. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the AT 2025azn Optical Candidate
  36. GRB 250129A: Continued AbAO and Mondy optical observations
  37. LIGO/Virgo/KAGRA S250206dm: SAGUARO Detection of Two Potential Optical Counterparts
  38. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  39. GRB 250207A: Swift detection of a burst with optical counterpart
  40. GRB 250205A: REM NIR upper limit
  41. EP250205a/GRB 250205A: FTW optical and NIR observations of the counterpart
  42. GRB 250127C: SVOM/GRM observation of a burst
  43. GRB 250204B: SVOM/GRM observation of a likely short burst
  44. GRB 250205A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  45. GRB 250205A: Swift/XRT detection
  46. GRB 250205A: Redshift from OSIRIS+/GTC z = 3.55
  47. GRB250205A: SVOM/VT optical afterglow detection
  48. GRB 250205A: GOTO optical upper limits
  49. GRB 250205A: OHP/T193 optical counterpart candidate
  50. GRB 250205A: Liverpool Telescope optical counterpart candidate detection
  51. GRB 250205A: SVOM detection of a burst
  52. GRB 250129A: LCO late afterglow detection
  53. GRB 250129A: AbAO AS-32 and Mondy AZT-33IK optical observations
  54. GRB 250129a: Liverpool Telescope optical follow-up
  55. GRB 240129A: further SAO RAS optical observations
  56. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
  57. GRB 250129A: SVOM/C-GFT optical observations
  58. GRB 250129A: 1.3m DFOT Optical observations
  59. GRB 250129A: Skynet Continued Optical Observations
  60. GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations
  61. GRB 250129A: SAO RAS optical observations
  62. GRB 250129A: optical photometry from Konkoly
  63. GRB 250129A: COLIBRÍ Optical Observations
  64. GRB 250128B: VLA possible radio detection
  65. GRB 250129A: iTelescope optical observation
  66. GRB 250129A: NOT optical observations of continuining activity
  67. GRB 250129a: Liverpool Telescope optical follow-up
  68. GRB 250129A: AKO Optical Afterglow Detection
  69. GRB 250129A: GRANDMA/TAROT optical afterglow detection
  70. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  71. Ep250125A: 1.3m DFOT optical upper limit
  72. GRB 250129A: Skynet optical observations
  73. GRB 250129A: KAIT optical observations of the rebrightening around 5.1 hours
  74. GRB 250128B: Gemini-North optical extended source detection
  75. GRB 250128B: TNG optical upper limit
  76. GRB 250129A: Swift/UVOT Detection
  77. GRB 250127A: CrAO and Terskol optical upper limits
  78. GRB 250128B: NOT optical upper limit
  79. GRB 250128B: VLT/FORS2 optical observations
  80. GRB 250129A: REM optical/NIR afterglow detection
  81. GRB 250129A: OHP/T193 optical and spectroscopy observations
  82. GRB 250129A: Early afterglow detection by LCO.
  83. GRB 250128B: OHP/T193 optical upper limit
  84. GRB 250129A: LCO optical observations
  85. GRB 250129A: NOT optical observations and redshift confirmation
  86. GRB 250129A: GOTO optical observations show brightening afterglow
  87. GRB 250129A: VLT/X-shooter redshift of z = 2.151
  88. GRB 250129A: Swift detection of a burst with an optical counterpart
  89. Swift GRB 250129A: Global MASTER-Net OT detection
  90. GRB 250128B: GOTO optical upper limit
  91. GRB 250128B: LCO optical observations
  92. GRB 250127A: LCO optical upper limit
  93. EP250125a: Optical upper limit with Kinder observations
  94. EP250125a: REM optical counterpart detection
  95. EP250125a: Swift/XRT detection of a fading counterpart
  96. EP250125a: a new X-ray transient detected by Einstein Probe
  97. EP250125a: Gemini-South optical afterglow discovery and redshift z = 2.89
  98. EP250108a: AbAO, CMO and Terskol optical upper limits
  99. EP250108a/AT2025kg: 1.3m DFOT Optical observations
  100. EP250108a / SN2025kg: Non-detection from ATCA radio follow-up observations

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