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"
  1. EP240414a: GMG observation
  2. GRB 240419A: Prompt enhanced Swift-XRT position
  3. GRB 240419A: Swift detection of a burst
  4. GRB 240418A: TSHAO Zeiss-1000 optical upper limit
  5. GRB 240418A: NOT optical upper limits
  6. GRB 240418A: Enhanced Swift-XRT position
  7. GRB 240418A: AKO Upper Limit
  8. GRB 240411A: GOTO early optical upper limits
  9. Swift GRB240418.85: Global MASTER-Net observations report
  10. GRB 240418A: Swift detection of a burst
  11. EP240417a: EP-WXT detection of a fast X-ray transient
  12. Fermi GRB 240417A: Global MASTER-Net observations report
  13. LIGO/Virgo/KAGRA S240413p: X-ray upper limits from EP-WXT for the candidate AGN counterpart
  14. EP240416A: Terskol Zeiss-2000 optical upper limit
  15. EP240416A: Khureltogoot optical upper limit
  16. Improved IPN triangulation of GRB 240411A
  17. EP240416a: BOOTES-2/TELMA Optical Upper Limit
  18. EP240414a: GSP detects optical candidate counterpart AT2024gsa
  19. LIGO/Virgo/KAGRA S240413p: DECam GW-MMADS candidates
  20. IceCube-Cascade 240416A: Upper limits from a search for additional neutrino events in IceCube
  21. GRB 240417A: Fermi GBM Final Real-time Localization
  22. EP240414a: Pan-STARRS detects re-brightening of the candidate counterpart AT2024gsa
  23. LIGO/Virgo/KAGRA S240413p: historical ATLAS and ZTF observations of the candidate AGN counterpart
  24. GRB 240415A: Glowbug gamma-ray detection
  25. GRB 240414A: Glowbug gamma-ray detection
  26. LIGO/Virgo/KAGRA S240413p: STEP - T80S Search and Candidate Counterpart Identification
  27. GRB 240415B: GECAM-B detection
  28. EP 240416a: Xinglong and NOT decaying optical counterpart
  29. GRB 240415A: Swift-BAT refined analysis
  30. EP240416A: MASTER optical observations
  31. GRB 240411A: Glowbug gamma-ray detection
  32. GRB 240414A: Swift-BAT refined analysis
  33. EP240416a: Kinder optical counterpart candidate
  34. EP240416a: EP-WXT detection of a fast X-ray transient
  35. GRB 240414A: AbAO optical upprer limit
  36. GRB 240415A: Swift/UVOT Detection
  37. EP240413a: BOOTES-2/TELMA Optical Upper Limit
  38. GRB 240415A: Fermi GBM Observation
  39. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  40. GRB 240415A: Earliest optical followup with the Kinder observations
  41. GRB 240414A: GMG observation
  42. EP 240414a: BOOTES-4/MET Optical Upper Limits
  43. EP240414a: EP-FXT follow-up observation
  44. GRB 240415A: Enhanced Swift-XRT position
  45. GRB 240415B: Swift ToO observations
  46. GRB 240415B: Swift/BAT-GUANO Correction
  47. GRB 240415B: Swift/BAT-GUANO arcminute localization of a short burst
  48. GRB 240415A: OHP/T193 optical observations
  49. GRB 240415A: optical afterglow detection from the INAF Asiago Observatory
  50. GRB 240415A: SAO RAS optical observations
  51. GRB 240415A: Mondy optical transient detection (photometry correction in GCN 36118 )
  52. GRB 240414A: Fermi GBM Observation
  53. Fermi GRB 240415A: Global MASTER-Net observations report
  54. GRB 240415A: Mondy optical transient detection
  55. GRB 240414A: Photometric observation from 2.2m CAHA
  56. IceCube-240412A: Upper limits from a search for additional neutrino events in IceCube
  57. GRB 240414A: Swift/UVOT Detection
  58. LXT 240402A/GRB 240402B: Swift follow-up observations
  59. GRB 240414A: Mondy optical observations
  60. GRB 240414B: Fermi GBM Final Real-time Localization
  61. GRB 240414A: AKO Optical Upper Limit
  62. X-ray transient EP 240414a - GTC spectroscopic observations
  63. GRB 240415A: Prompt Swift-XRT observations
  64. GRB 240415A: Swift detection of a burst
  65. GRB 240415A: Fermi GBM Final Real-time Localization
  66. EP240413a: Upper limits from GECAM-B Observation
  67. EP 240414a: NOT optical counterpart confirmation
  68. GRB 240414A: Swift-XRT refined Analysis
  69. GRB240414A : J-band upper limits from WINTER
  70. GRB 240414A: Enhanced Swift-XRT position
  71. GRB 240414A : OHP/T193 second epoch of optical follow-up and afterglow detection
  72. GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  73. LIGO/Virgo/KAGRA S240413p: No Counterparts in DDOTI/OAN Optical Observations
  74. EP240413A: GOTO optical upper limits
  75. GRB 240414A: Skynet Optical Afterglow Observations
  76. Fermi trigger No 734754044: Global MASTER-Net observations report
  77. Swift GRB 240414A: Global MASTER-Net observations report
  78. EP240414a: Kinder optical counterpart candidate possibly associated with the galaxy SDSS J124601.99-094309.3
  79. IPN triangulation of GRB 240410A
  80. EP240413a: possible detection of the X-ray emission with EP-FXT after 14 hours
  81. EP240414a: EP-WXT detection of a fast X-ray transient
  82. IPN triangulation of GRB 240411A
  83. Fermi-LAT gamma-ray observations of IceCube-240412A
  84. GRB 240414A : MITSuME Akeno optical upper limits
  85. GRB 240414A: Redshift confirmation from GTC/OSIRIS+
  86. EP240413a: EP-WXT detection of a fast X-ray transient
  87. GRB 240414A : OHP/T193 redshift determination
  88. GRB 240414A : OHP/T193 optical counterpart detection
  89. GRB 240414A: Swift detection of a burst
  90. LIGO/Virgo/KAGRA S240413p: Updated Sky localization
  91. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  92. LIGO/Virgo/KAGRA S240413p: Zwicky Transient Facility observations
  93. EP240408a: GSP optical upper limit
  94. GRB 240411B: CrAO/ZTSh optical observations
  95. GRB 240411B: Kinder observations with Lulin observatory
  96. LIGO/Virgo/Kagra S240413p: NED Galaxies in the Localization Volume
  97. LIGO/Virgo/KAGRA S240413p: Identification of a GW compact binary merger candidate
  98. GRB 240411B: HiPERCAM/GTC observation
  99. IceCube Alert 240412.23: Global MASTER-Net observations report
  100. GRB 240411B: Swift-BAT refined analysis

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