Skip to main content
Due to the lapse in federal government funding, NASA is not updating this website. See the Operations FAQ for GCN impacts.
New! Super-Kamiokande JSON Notices and Schema v4.5.0. See news and announcements

GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

26016 results found.

  1. GRB 251103B: Swift-BAT refined analysis
  2. GRB 251106A: Swift/UVOT Upper Limits
  3. LIGO/Virgo/KAGRA S251108fi: DDOTI Optical Candidate
  4. LIGO/Virgo/KAGRA S251108fi: One counterpart neutrino candidate from IceCube neutrino searches
  5. IceCube-Cascade 251107A: Upper limits from a search for additional neutrino events in IceCube
  6. LIGO/Virgo/KAGRA S251108fi: Updated Sky localization
  7. LIGO/Virgo/KAGRA S251108dn: Updated Sky localization
  8. Fermi trigger No 784329591: Global MASTER-Net observations report
  9. LIGO/Virgo/KAGRA S251108fi: Identification of a GW compact binary merger candidate
  10. Fermi trigger No 784279167: Global MASTER-Net observations report
  11. SVOM GRB251108.54: Global MASTER-Net observations report
  12. GRB 251102B: SVOM/GRM observation
  13. LIGO/Virgo/KAGRA S251108dn: Identification of a GW compact binary merger candidate
  14. SVOM GRB251106.83: Global MASTER-Net observations report
  15. LIGO/Virgo/KAGRA S251105aj: Updated Sky localization
  16. LIGO/Virgo/KAGRA S251103f: Updated Sky localization
  17. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) fading of the optical counterpart
  18. GRB 251106A: Swift-XRT afterglow detection
  19. GRB 251106A: Kilonova-Catcher optical upper limit
  20. Fermi GBM Sub-Threshold Detection of GRB 251106A
  21. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) detection of a likely optical counterpart
  22. GRB 251106A: MASTER optical observations
  23. GRB 251025C: TERI Gamma-ray detection
  24. GRB 251016B: TERI Gamma-ray detection
  25. GRB 251016A: TERI Gamma-ray detection of a short burst
  26. GRB 250920C: TERI Gamma-ray detection
  27. Fermi trigger No 784034269: Global MASTER-Net observations report
  28. EP251102a: Xinglong 2.16-m clear-band observations of the optical counterpart
  29. GRB 251105A: Fermi GBM Observation
  30. GRB 251105A: Swift/BAT-GUANO localization skymap of a burst
  31. GRB 251104A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  32. Fermi GBM Sub-Threshold Detection of GRB 251105B
  33. GRB 251103B: Swift/UVOT Upper Limits
  34. LIGO/Virgo/KAGRA S251105aj: Identification of a GW compact binary merger candidate
  35. GRB 251103B: Fermi GBM observation
  36. GRB 251103A: WFST optical observations
  37. GRB 251103A: OHP/T193 optical observations
  38. GRB 251103A: Xinglong 2.16m optical detection
  39. GRB 251103A: KAIT optical observations
  40. GRB 251103B: Nanshan/HMT optical upper limit
  41. GRB 251013C: 7DT detection and Medium-band SED of Afterglow
  42. GRB 251103A: Swift/BAT-GUANO arcminute localization of a burst
  43. GRB 251103B: MITSuME Akeno optical upper limits
  44. GRB 251103B: Swift-XRT refined Analysis
  45. LIGO/Virgo/KAGRA S251103f: Identification of a GW compact binary merger candidate
  46. EP251102a: NIR observations with WINTER
  47. GRB 251103A: J-band detection with WINTER
  48. GRB 251103B: GROWTH-India Telescope optical upper limits
  49. GRB 251103A: Kilonova-Catcher optical afterglow detection
  50. GRB 251103B: Enhanced Swift-XRT position
  51. GRB 251103B: Swift detection of a burst
  52. GRB 251103A: Swift/UVOT Detection
  53. GRB 251103A: Fermi GBM Observation
  54. GRB 251103A: Swift-XRT afterglow detection
  55. LIGO/Virgo/KAGRA S251031cq: Updated Sky localization
  56. GRB 251103A: SVOM/COLIBRÍ (FM-GFT) optical observations
  57. EP251102a: Einstein Probe detection of a fast X-ray transient
  58. EP251102a (WXT 11900459650): LCO observations confirm COLIBRÍ candidate
  59. GRB 251103A: LCO optical observation
  60. EP251102.890: COLIBRÍ optical counterpart candidate
  61. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical counterpart
  62. GRB 251103A: LCO optical afterglow detection
  63. GRB 251103A: NOT optical afterglow candidate
  64. GRB 251031A: Fermi GBM Observation
  65. LIGO/Virgo/KAGRA S251031cq: Identification of a GW compact binary merger candidate
  66. GRB 251031A: Swift/BAT-GUANO localization skymap of a burst
  67. GRB 251031A: BALROG localization (Fermi Trigger 783588065 / GRB 251031306)
  68. GRB 251025C: SVOM/GRM observation
  69. GRB 251028A: SVOM/GRM observation
  70. GRB 251028A: Fermi GBM Observation
  71. GRB 251022A: Swift-XRT confirmation of fading
  72. GRB 250926A: VZLUSAT-2 detection
  73. GRB 251026B: Fermi GBM Observation
  74. GRB 251026A/EP251026a: SVOM/VT optical counterpart
  75. GRB 251028B: Swift/BAT-GUANO localization skymap of a burst
  76. GRB 251028B: Glowbug gamma-ray detection
  77. GRB 251028A: Glowbug gamma-ray detection
  78. GRB 251025B: GROWTH-India Telescope continued multiband optical observations and rebrightening
  79. GRB251026B: PRIME H-band upper limit
  80. GRB251025B: 3.6m DOT Optical Observations
  81. GRB 251028A: BALROG localization (Fermi Trigger 783314796 / GRB 251028143)
  82. GRB 251028A: MAXI/GSC detection
  83. SVOM trigger sb25102702/GRB 251027A is not a GRB
  84. IceCube-251025A: Upper limits from a search for additional neutrino events in IceCube
  85. GRB 251013C : 3.4-m telescope of Iranian National Observatory (INO340) optical observations
  86. GRB 251026B: Swift-XRT observations of GOTO25jgl/AT2025absf
  87. GRB 251025C: Glowbug gamma-ray detection
  88. Fermi-LAT Gamma-ray Observations of IceCube-251025A
  89. GRB 251027A: Swift-XRT observations
  90. EP251027.145: COLIBRÍ optical upper limits
  91. GRB 251022A: SVOM/GRM observation
  92. GRB 251026A/EP251026a: Einstein Probe detection of a fast X-ray transient
  93. GRB 251027A: LCO optical upper limit
  94. GRB 251027A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  95. GRB 251017A: Mondy AZT-33IK and Koshka Zeiss-1000 optical observations
  96. GRB 251023B / EP251023b: Mondy optical upper limit
  97. GRB 251017A: INASAN-Kislovodsk optical observations
  98. GRB 251026A: Mondy optical upper limit
  99. GRB 251025B: Mondy optical observations
  100. GRB 251025B: Kilonova-Catcher optical afterglow detection

Advanced

Download all Circulars as a .tar.gz archive:
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