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"

19577 results found.

  1. GRB 250215A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  2. GRB 250215A/EP250215a: 1.6m Mephisto optical observation report
  3. GRB 250213A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  4. GRB 250215A: SVOM/GRM observation
  5. EP250215a / GRB 250215A: AstroSat CZTI detection
  6. EP250215a / GRB 250215A (potentially): NOT likely optical counterpart
  7. EP250215a: EP-WXT detection and FXT follow-up observation of an X-ray transient
  8. EP250207b: Xinglong optical upper limit
  9. GRB 250213A: Swift ToO observations
  10. EP250212a: Xinglong optical upper limit
  11. LIGO/Virgo/KAGRA S250206dm: DECam GW-MMADS candidates
  12. GRB 250213A: SVOM detection of a burst
  13. GRB 250205A: VIRT Optical Upper Limit
  14. GRB 250205A: Leavitt Observatory optical upper limit
  15. EP250207B: Chandra localization of the X-ray counterpart
  16. EP250212a: Liverpool Telescope optical upper limits
  17. GRB250101A: Radio upper limits from GMRT observations
  18. EP trigger 10202399251 (possibly EP250212a): NOT J-band upper limit
  19. EP250207B: GTC z-band Observations
  20. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Follow-up of AT2025ber
  21. GRB 250205A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  22. EP250207b: NOT optical counterpart candidate
  23. LIGO/Virgo/KAGRA S250206dm: GECKO Continued Observaiton with 7DT
  24. GRB 250211A: Swift ToO observations
  25. LIGO/Virgo/KAGRA S250206dm: AT 2025bbo observations with WFST
  26. GRB 250206A: Fermi GBM Observation
  27. GRB 250205A / EP250205A: radio detection with the VLA
  28. EP250207b: Tentative z-band brightening source
  29. LIGO/Virgo/KAGRA S250206dm: Kinder confirmation of a possible artefact in AT 2025bbo
  30. GRB 250210A: SVOM/GRM observation of a long burst
  31. EP250207b: Liverpool Telescope possible optical counterpart
  32. LIGO/Virgo/KAGRA S250211aa: Identification of a GW compact binary merger candidate
  33. GRB 250207A: Skynet optical afterglow observations
  34. GRB 241128A: VIRT Optical Upper Limit
  35. EP250207b: Gemini GMOS-N z-band observations
  36. EP250207b: a new X-ray transient detected by Einstein Probe
  37. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of AT2025bbo and Galaxies in the Localization Volume
  38. LIGO/Virgo/KAGRA S250206dm: Observations from WINTER
  39. LIGO/Virgo/KAGRA S250206dm: Optical observations of candidate AT 2025bbo with Kinder
  40. Fermi-LAT Gamma-ray Observations of IceCube-250207A
  41. GRB 250207A: 1.3m DFOT Optical observations
  42. LIGO/Virgo/KAGRA S250206dm: WFST follow-up observations
  43. LIGO/Virgo/KAGRA S250206dm: FRB 20250206A BOOTES-5 and 2.2m CAHA optical upper limits
  44. GRB 250129A: GRANDMA Continued Afterglow Detection
  45. LIGO/Virgo/KAGRA S250206dm: GECKO Observation with 7DT and KMTNet
  46. GRB 250205A: 1.3m DFOT optical upper limit
  47. GRB 250206A: Tiled Swift observations
  48. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Observations
  49. GRB 250207B: Swift-XRT observations
  50. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the DDOTI optical candidates
  51. GRB 250208A: Fermi GBM Final Real-time Localization
  52. LIGO/Virgo/KAGRA S250208ad: Identification of a GW compact binary merger candidate
  53. EP trigger 01709131361 (possible EP250207a): NOT optical observations and flaring star
  54. GRB 250207A: Enhanced Swift-XRT position
  55. 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%
  56. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  57. GRB 250207A: REM IR afterglow detection
  58. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limits
  59. GRB 250207B: Tiled Swift observations
  60. IGO/Virgo/KAGRA S250206dm: Virtual Telescope Project upper limit for the Neutrino IceCube Candidate
  61. GRB 250207A: REM optical afterglow detection
  62. GRB 250207A: Swift/UVOT Detection
  63. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limit for the Neutrino IceCube Candidate
  64. LIGO/Virgo/KAGRA S250206dm: GOTO observations of optical candidates AT 2025azn and AT 2025azm
  65. LIGO/Virgo/KAGRA S250206dm: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  66. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the AT 2025azn Optical Candidate
  67. GRB 250129A: Continued AbAO and Mondy optical observations
  68. LIGO/Virgo/KAGRA S250206dm: SAGUARO Detection of Two Potential Optical Counterparts
  69. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  70. GRB 250207A: Swift detection of a burst with optical counterpart
  71. LIGO/Virgo/KAGRA S250206dm: Identification of a GW compact binary merger candidate
  72. GRB 250205A: REM NIR upper limit
  73. GRB 250205A: Swift/UVOT Upper Limits
  74. EP250205a/GRB 250205A: Einstein Probe observation
  75. GRB 250127C: SVOM/GRM observation of a burst
  76. GRB 250204B: SVOM/GRM observation of a likely short burst
  77. GRB 250205A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  78. GRB 250205A: Redshift from OSIRIS+/GTC z = 3.55
  79. GRB250205A: SVOM/VT optical afterglow detection
  80. GRB 250205A: OHP/T193 optical counterpart candidate
  81. LIGO/Virgo/KAGRA S250205ee: Identification of a GW compact binary merger candidate
  82. GRB 250205A: SVOM detection of a burst
  83. Konus-Wind detection of GRB 250201A
  84. IPN triangulation of GRB 250201A
  85. Konus-Wind detection of GRB 250202B
  86. IPN triangulation of GRB 250202B
  87. GRB 250204B: AstroSat CZTI detection of a short burst
  88. GRB 250129A: LCO late afterglow detection
  89. GRB 250129A: AbAO AS-32 and Mondy AZT-33IK optical observations
  90. LIGO/Virgo/KAGRA S250204ax: Identification of a GW compact binary merger candidate
  91. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  92. GRB 250129a: Liverpool Telescope optical follow-up
  93. GRB 240129A: further SAO RAS optical observations
  94. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
  95. GRB 250129A: SVOM/C-GFT optical observations
  96. GRB 250202B: AstroSat CZTI detection of a bright long GRB
  97. Swift GRB250129A: MASTER 4 days observations report
  98. Konus-Wind detection of GRB 250129A
  99. GRB 250129A: 1.3m DFOT Optical observations
  100. GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical 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