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"

45888 results found.

  1. IceCube-261020A: Upper limits from a search for additional neutrino events in IceCube
  2. NuSTAR 261020, a 830s hard X-ray transient
  3. EP261015a: GSP multiband optical follow-up observations
  4. GRB 261017A: SVOM/GRM observation
  5. GRB 261021A: Fermi GBM Final Real-time Localization
  6. EP261015a: Further optical observations with the 1.3m DFOT
  7. GRB 261020B: AstroSat CZTI detection of a short burst
  8. Fermi-LAT Gamma-ray Observations of IceCube-261020A
  9. EP261015a: AZT-20 Assy-Turgen optical observations
  10. GRB 261020A: Fermi GBM Observation
  11. GRB 261017A: SAO RAS optical upper limit
  12. EP261015a: Wendelstein 43 cm optical observations
  13. GRB 260903A
  14. EP261015a: Follow-up with the 1.3m DFOT
  15. EP261015a: Terskol Zeiss-2000 optical upper limit
  16. EP261007b: Further EP-FXT follow-up observations
  17. GRB 261017A: COLIBRÍ optical upper limit
  18. IceCube-261020A - IceCube observation of a high-energy neutrino candidate track-like event
  19. GRB 261020A: MAXI GSC detection
  20. GRB 261020A: Fermi GBM Final Real-time Localization
  21. EP261015a: COLIBRÍ optical observations of a rebrightening
  22. Konus-Wind detection of GRB 261017A
  23. GRB 261019A: Fermi GBM Final Localization
  24. GRB 261017A: Possible Swift/UVOT Detection
  25. GRB 261017A: Luminance-band upper limit from a 28cm telescope in Chengde
  26. GRB 261017A: R-band upper limit with the 1.3-m DFOT
  27. GRB 261017A: Swift-BAT refined analysis
  28. GRB 261017A: a short minimum variability timescale compatible with a compact object merger origin
  29. EP261015b: NOT Optical Observations
  30. GRB 261017A: J band upper limit by the SYSU 80cm infrared telescope
  31. EP261015c: refined analysis of the EP-FXT observation favors a stellar flare interpretation
  32. GRB 261017A : MITSuME Akeno optical upper limits
  33. GRB 261017A: Swift-XRT refined Analysis
  34. GRB 261017A: Nanshan/NEXT optical upper limit
  35. GRB 261017A: Enhanced Swift-XRT position
  36. GRB 261017A: Fermi GBM Observation
  37. GRB261010A: Retraction of Keck/MOSFIRE near-IR source
  38. GRB 261017A: Swift detection of a burst
  39. GRB 261017A: Fermi GBM Final Real-time Localization
  40. EP261015a: Tentative fading of the candidate optical counterpart from the NOT
  41. EP261015b: Refined analysis of EP-FXT observations
  42. EP261015b: J-band upper limit by the SYSU 80cm infrared telescope
  43. EP261015a: refined analysis of EP-FXT observations
  44. EP261015c: J-band upper limit with WINTER
  45. EP261015a: J-band upper limit with WINTER
  46. EP261006a / AT 2026aetp: Optical follow-up with the 1.3-m DFOT
  47. GRB 261011A: 1.3m DFOT optical upper limit
  48. GRB 261010A: Pan-STARRS z-band imaging and upper limit
  49. EP261015a: SVOM/VT optical observation
  50. EP241111a and EP250125a: Upper limits from SVOM/GRM Observations
  51. GRB 261010A: VLA radio observations
  52. EP261015a: COLIBRÍ optical observations
  53. EP261015c: Einstein Probe detection of a fast X-ray transient
  54. EP261015b: Einstein Probe detection of an X-ray transient
  55. GRB261010A: Keck/MOSFIRE detection of a near-IR source
  56. EP261015a: Einstein Probe detection of a fast X-ray transient
  57. EP261015a (WXT 11900947714): Possible optical counterpart from NOT and LCO
  58. The EP-WXT trigger 01709321333 is likely a flaring star
  59. GRB 261010A: ASKAP non-detection of a radio afterglow
  60. GRB 261010A: LBT tentative near-infrared detection
  61. GRB 261011A: SAO RAS and AbAO optical observations
  62. GRB 261010A: Glowbug gamma-ray detection
  63. GRB 261008A: SVOM/GRM observation
  64. GRB 261009A: GECAM-B detection of a burst
  65. EP261006a : MeerKAT radio observations.
  66. IceCube-261012A: Upper limits from a search for additional neutrino events in IceCube
  67. GRB 261010A: initial pulse rest-frame energetics from Konus-Wind detection
  68. GRB 261010A: a short minimum variability timescale and a distinct pulse evolution compatible with a merger origin
  69. GRB 261013A: Fermi GBM Final Real-time Localization
  70. GRB 261011A: Later-epoch J-band upper limit from the SYSU 80 cm infrared telescope
  71. Fermi-LAT Gamma-ray Observations of IceCube-261012A
  72. GRID detection of GRB 261010A
  73. GRB 261011A: GECAM-B observation
  74. GRB 261011B: GECAM-B observation
  75. GRB 261010A: J-band upper limit by the SYSU 80cm infrared telescope
  76. IceCube-260919A: No transient candidates from the Zwicky Transient Facility
  77. GRB 261010A: Swift-XRT refined Analysis
  78. GRB 261011A: Swift-XRT refined Analysis
  79. GRB 261011A: Enhanced Swift-XRT position
  80. GRB 261010A: a Type I-L (merger-driven) GRB candidate
  81. GRB 261011A: 10.4m GTC spectroscopic redshift (z = 2.407)
  82. GRB 261011A: Swift-BAT refined analysis
  83. IceCube-261012A - IceCube observation of a high-energy neutrino candidate track-like event
  84. GRB 261010A: 10.4m GTC spectroscopy of the galaxy 2" from the afterglow
  85. MAXI GRB261012.23: Global MASTER-Net observations report
  86. GRB 261011A: REM optical/NIR observations
  87. Konus-Wind detection of GRB 261010A
  88. Konus-Wind detection of GRB 261011A
  89. Konus-Wind detection of GRB 261007A/EP261007a
  90. GRB 261011A: SOAR optical afterglow observations at ~17 hours
  91. EP261006a: 10 GHz VLA observations
  92. GRB 261011A: VLT/X-shooter redshift constraints
  93. GRB 261012A: MAXI GSC detection
  94. GRB 261010A: Swift-BAT refined analysis
  95. GRB 261011A : MITSuME Akeno optical afterglow candidate detection
  96. GRB 261011A: Optical followup from Sichuan South Observatory
  97. GRB 261011A: GMG Optical Observation
  98. GRB 261011A: Liverpool Telescope optical observations
  99. GRB 261011A: J-band observations by the SYSU 80cm infrared telescope
  100. GRB 261010A: NOT confirmation of the optical afterglow

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