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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"

38681 results found.

  1. Swift Trigger 1413695: a possible GRB 251112A
  2. LIGO/Virgo/KAGRA S251112cm: Upper limits from Fermi-GBM Observations
  3. LIGO/Virgo/KAGRA S251112cm: NED Galaxies in the 3-Initial Localization Volume
  4. Fermi Gamma-ray Burst Monitor trigger 784653403/251112637 is not a GRB
  5. GRB251111A: 1.3m DFOT optical upper limit
  6. GRB 251106B: Glowbug gamma-ray detection of a likely short burst
  7. GRB 251111A: Swift-XRT afterglow detection
  8. GRB 251111A: SVOM/VT optical observations with X-band data
  9. SVOM GRB251111.42: Global MASTER-Net observations report
  10. GRB 251111A: Swift-XRT observations
  11. SVOM GRB251111.22: Global MASTER-Net observations report
  12. GRB 251111A: EP-FXT counterpart detection
  13. GRB 251013C: Chandra X-ray observations and jet break detection
  14. GRB 251111A: SVOM/VT optical observations with VHF data
  15. GRB 251111A: KAIT optical upper limit
  16. GRB 251111A: LCO optical observation
  17. GRB 251111A: SVOM/COLIBRÍ (FM-GFT) optical counterpart detection
  18. GRB 251111A: SVOM detection of a soft burst
  19. GRB 251106A: Swift/UVOT Upper Limits
  20. GRB 251105B: Insight-HXMT/HE detection
  21. GRB 251106B: Insight-HXMT detection
  22. LIGO/Virgo/KAGRA S251108fi: DDOTI Optical Candidate
  23. GRB 251105A: AstroSat CZTI detection
  24. LIGO/Virgo/KAGRA S251108fi: One counterpart neutrino candidate from IceCube neutrino searches
  25. IceCube-Cascade 251107A: Upper limits from a search for additional neutrino events in IceCube
  26. GRB 251108A: Fermi GBM Final Localization Correction
  27. SVOM GRB251108.54: Global MASTER-Net observations report
  28. GRB 251102B: SVOM/GRM observation
  29. Fermi Gamma-ray Burst Monitor trigger 784279167/251108305 is not a GRB
  30. The EP-WXT trigger 01709248051 is likely a flaring star
  31. SVOM GRB251106.83: Global MASTER-Net observations report
  32. IPN triangulation of GRB 251105B (possible sGRB with EE)
  33. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) fading of the optical counterpart
  34. GRB 251106B: SVOM/GRM observation of a short burst
  35. GRB 251106A: Swift-XRT afterglow detection
  36. GRB 251106A: Kilonova-Catcher optical upper limit
  37. Fermi GBM Sub-Threshold Detection of GRB 251106A
  38. GRB 251106A: Swift/BAT arcminute localization of a burst
  39. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) detection of a likely optical counterpart
  40. GRB 251106A: MASTER optical observations
  41. GRB 251106A: SVOM detection of a burst
  42. GRB 251103B: AstroSat CZTI detection
  43. GRB 251025C: TERI Gamma-ray detection
  44. GRB 251016B: TERI Gamma-ray detection
  45. GRB 251016A: TERI Gamma-ray detection of a short burst
  46. GRB 250920C: TERI Gamma-ray detection
  47. Fermi Gamma-ray Burst Monitor trigger 784109140/251106337 is not a GRB
  48. EP251102a: Xinglong 2.16-m clear-band observations of the optical counterpart
  49. GRB 251105A: Fermi GBM Observation
  50. GRB 251105C: Fermi GBM Final Localization Correction
  51. LIGO/Virgo/KAGRA S251031dw: Candidates from the Zwicky Transient Facility
  52. GRB 251105A: Swift/BAT-GUANO localization skymap of a burst
  53. GRB 251104A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  54. GRB 251105B: AstroSat CZTI detection of a short burst with extended emission
  55. GRB 251023A: SVOM/ECLAIRs detection of a burst through targeted search
  56. Fermi GBM Sub-Threshold Detection of GRB 251105B
  57. GRB 251103B: Swift/UVOT Upper Limits
  58. GRB 251105B: SVOM/GRM observation of a possible short burst with extended emission
  59. GRB 251105A: Fermi GBM Final Real-time Localization
  60. Fermi Gamma-ray Burst Monitor trigger 783986701/251104920 is not a GRB
  61. GRB 251103B: Fermi GBM observation
  62. GRB 251104A: SVOM detection of a burst
  63. GRB 251028A: Insight-HXMT/HE detection
  64. GRB 251103A: Optical afterglow detection by ZTF’s public survey
  65. GRB 251103A: WFST optical observations
  66. EP251102a: update of EP-FXT follow-up observation
  67. EP251102a: OHP/T193 optical observations
  68. GRB 251103A: OHP/T193 optical observations
  69. GRB 251103A: Xinglong 2.16m optical detection
  70. GRB 251103A: Insight-HXMT detection
  71. GRB 251103A: KAIT optical observations
  72. GRB 251103B: Nanshan/HMT optical upper limit
  73. GRB 251013C: 7DT detection and Medium-band SED of Afterglow
  74. GRB 251103A: Swift/BAT-GUANO arcminute localization of a burst
  75. GRB 251103B: MITSuME Akeno optical upper limits
  76. GRB 251103B: Swift-XRT refined Analysis
  77. GRB 251103B: GROWTH-India Telescope optical upper limits
  78. GRB 251103A: Kilonova-Catcher optical afterglow detection
  79. GRB 251103B: Enhanced Swift-XRT position
  80. GRB 251103B: Prompt enhanced Swift-XRT position
  81. GRB 251103B: Swift detection of a burst
  82. GRB 251103B: Fermi GBM Final Real-time Localization
  83. GRB 251103A: Swift/UVOT Detection
  84. GRB 251103A: Fermi GBM Observation
  85. GRB 251103A: SVOM/GRM observation
  86. GRB 251103A: Swift-XRT afterglow detection
  87. GRB 251103A: SVOM/COLIBRÍ (FM-GFT) optical observations
  88. EP251102a: Einstein Probe detection of a fast X-ray transient
  89. GRB 251025B: OHP/T193 optical upper limit
  90. EP251102a (WXT 11900459650): LCO observations confirm COLIBRÍ candidate
  91. GRB 251103A: LCO optical observation
  92. EP251102.890: COLIBRÍ optical counterpart candidate
  93. GRB 251103A: GOTO optical afterglow detection
  94. GRB 251102A: AstroSat CZTI detection
  95. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical counterpart
  96. GRB 251103A: NOT spectroscopic redshift z = 0.76
  97. GRB 251103A: BOOTES-2/TELMA optical afterglow
  98. GRB 251103A: LCO optical afterglow detection
  99. GRB 251103A: Fermi GBM Final Localization
  100. GRB 251103A: NOT optical afterglow candidate

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