Skip to main content
New! BOOM Notices and Schema v7.0.0. 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"

27326 results found.

  1. GRB 251111A: SVOM/VT optical observations with X-band data
  2. SVOM GRB251111.42: Global MASTER-Net observations report
  3. GRB 251111A: Swift-XRT observations
  4. SVOM GRB251111.22: Global MASTER-Net observations report
  5. GRB 251111A: EP-FXT counterpart detection
  6. GRB 251013C: Chandra X-ray observations and jet break detection
  7. GRB 251111A: SVOM/VT optical observations with VHF data
  8. GRB 251111A: LCO optical observation
  9. GRB 251111A: SVOM/COLIBRÍ (FM-GFT) optical counterpart detection
  10. GRB 251103B: Swift-BAT refined analysis
  11. GRB 251106A: Swift/UVOT Upper Limits
  12. LIGO/Virgo/KAGRA S251108fi: DDOTI Optical Candidate
  13. LIGO/Virgo/KAGRA S251108fi: One counterpart neutrino candidate from IceCube neutrino searches
  14. IceCube-Cascade 251107A: Upper limits from a search for additional neutrino events in IceCube
  15. LIGO/Virgo/KAGRA S251108fi: Updated Sky localization
  16. LIGO/Virgo/KAGRA S251108dn: Updated Sky localization
  17. Fermi trigger No 784329591: Global MASTER-Net observations report
  18. LIGO/Virgo/KAGRA S251108fi: Identification of a GW compact binary merger candidate
  19. Fermi trigger No 784279167: Global MASTER-Net observations report
  20. SVOM GRB251108.54: Global MASTER-Net observations report
  21. GRB 251102B: SVOM/GRM observation
  22. LIGO/Virgo/KAGRA S251108dn: Identification of a GW compact binary merger candidate
  23. SVOM GRB251106.83: Global MASTER-Net observations report
  24. LIGO/Virgo/KAGRA S251105aj: Updated Sky localization
  25. LIGO/Virgo/KAGRA S251103f: Updated Sky localization
  26. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) fading of the optical counterpart
  27. GRB 251106A: Swift-XRT afterglow detection
  28. GRB 251106A: Kilonova-Catcher optical upper limit
  29. Fermi GBM Sub-Threshold Detection of GRB 251106A
  30. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) detection of a likely optical counterpart
  31. GRB 251106A: MASTER optical observations
  32. GRB 251025C: TERI Gamma-ray detection
  33. GRB 251016B: TERI Gamma-ray detection
  34. GRB 251016A: TERI Gamma-ray detection of a short burst
  35. GRB 250920C: TERI Gamma-ray detection
  36. Fermi trigger No 784034269: Global MASTER-Net observations report
  37. EP251102a: Xinglong 2.16-m clear-band observations of the optical counterpart
  38. GRB 251105A: Fermi GBM Observation
  39. GRB 251105A: Swift/BAT-GUANO localization skymap of a burst
  40. GRB 251104A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  41. Fermi GBM Sub-Threshold Detection of GRB 251105B
  42. GRB 251103B: Swift/UVOT Upper Limits
  43. LIGO/Virgo/KAGRA S251105aj: Identification of a GW compact binary merger candidate
  44. GRB 251103B: Fermi GBM observation
  45. GRB 251103A: WFST optical observations
  46. GRB 251103A: OHP/T193 optical observations
  47. GRB 251103A: Xinglong 2.16m optical detection
  48. GRB 251103A: KAIT optical observations
  49. GRB 251103B: Nanshan/HMT optical upper limit
  50. GRB 251013C: 7DT detection and Medium-band SED of Afterglow
  51. GRB 251103A: Swift/BAT-GUANO arcminute localization of a burst
  52. GRB 251103B: MITSuME Akeno optical upper limits
  53. GRB 251103B: Swift-XRT refined Analysis
  54. LIGO/Virgo/KAGRA S251103f: Identification of a GW compact binary merger candidate
  55. EP251102a: NIR observations with WINTER
  56. GRB 251103A: J-band detection with WINTER
  57. GRB 251103B: GROWTH-India Telescope optical upper limits
  58. GRB 251103A: Kilonova-Catcher optical afterglow detection
  59. GRB 251103B: Enhanced Swift-XRT position
  60. GRB 251103B: Swift detection of a burst
  61. GRB 251103A: Swift/UVOT Detection
  62. GRB 251103A: Fermi GBM Observation
  63. GRB 251103A: Swift-XRT afterglow detection
  64. LIGO/Virgo/KAGRA S251031cq: Updated Sky localization
  65. GRB 251103A: SVOM/COLIBRÍ (FM-GFT) optical observations
  66. EP251102a: Einstein Probe detection of a fast X-ray transient
  67. EP251102a (WXT 11900459650): LCO observations confirm COLIBRÍ candidate
  68. GRB 251103A: LCO optical observation
  69. EP251102.890: COLIBRÍ optical counterpart candidate
  70. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical counterpart
  71. GRB 251103A: LCO optical afterglow detection
  72. GRB 251103A: NOT optical afterglow candidate
  73. GRB 251031A: Fermi GBM Observation
  74. LIGO/Virgo/KAGRA S251031cq: Identification of a GW compact binary merger candidate
  75. GRB 251031A: Swift/BAT-GUANO localization skymap of a burst
  76. GRB 251031A: BALROG localization (Fermi Trigger 783588065 / GRB 251031306)
  77. GRB 251025C: SVOM/GRM observation
  78. GRB 251028A: SVOM/GRM observation
  79. GRB 251028A: Fermi GBM Observation
  80. GRB 251022A: Swift-XRT confirmation of fading
  81. GRB 250926A: VZLUSAT-2 detection
  82. GRB 251026B: Fermi GBM Observation
  83. GRB 251026A/EP251026a: SVOM/VT optical counterpart
  84. GRB 251028B: Swift/BAT-GUANO localization skymap of a burst
  85. GRB 251028B: Glowbug gamma-ray detection
  86. GRB 251028A: Glowbug gamma-ray detection
  87. GRB 251025B: GROWTH-India Telescope continued multiband optical observations and rebrightening
  88. GRB251026B: PRIME H-band upper limit
  89. GRB251025B: 3.6m DOT Optical Observations
  90. GRB 251028A: BALROG localization (Fermi Trigger 783314796 / GRB 251028143)
  91. GRB 251028A: MAXI/GSC detection
  92. SVOM trigger sb25102702/GRB 251027A is not a GRB
  93. IceCube-251025A: Upper limits from a search for additional neutrino events in IceCube
  94. GRB 251013C : 3.4-m telescope of Iranian National Observatory (INO340) optical observations
  95. GRB 251026B: Swift-XRT observations of GOTO25jgl/AT2025absf
  96. GRB 251025C: Glowbug gamma-ray detection
  97. Fermi-LAT Gamma-ray Observations of IceCube-251025A
  98. GRB 251027A: Swift-XRT observations
  99. EP251027.145: COLIBRÍ optical upper limits
  100. GRB 251022A: SVOM/GRM observation

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