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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"

27030 results found.

  1. GRB 261024D: NuSTAR detection of prompt emission
  2. GRB 261024C: NuSTAR detection of prompt emission
  3. GRB 261026A: Ondrejov D50 optical limit
  4. GRB 261026A: ULL-ASTRO-MASTER optical detection with LCO 40-cm telescope at Haleakalā Observatory
  5. GRB 261026A: J-band observations by the SYSU 80cm infrared telescope
  6. GRB 261026A: SVOM/VT optical observations
  7. IPN triangulation of GRB 260730B
  8. GRB 261026C: Fermi GBM Final Real-time Localization
  9. GRB 261020A: Insight-HXMT/HE detection
  10. GRB 261026A: WINTER J-band observations
  11. GRB 261024D: AstroSat CZTI detection of a long burst
  12. GRB 261024C: AstroSat CZTI detection of a long burst
  13. GRB 261019A: GECAM-B observation
  14. GRB 261019A: SVOM/GRM observation
  15. GRB 261026A: SVOM/VT optical observation from VHF data
  16. GRB 261026A: KAIT optical observations
  17. GRB 261026B: Fermi GBM Final Real-time Localization
  18. GRB 261024A: NuSTAR detection of prompt emission
  19. GRB 261026A: SVOM detection of a burst
  20. GRB 261025B: Fermi GBM Final Real-time Localization
  21. EP261025a: J-band upper limit with WINTER
  22. EP261023a: J-band upper limit with WINTER
  23. EP261025a: Einstein Probe detection of a fast X-ray transient
  24. GRB 261025A: Fermi GBM Final Localization Correction
  25. EP261023a: J band upper limit by SYSU 80cm infrared telescope
  26. GRB 261024B: Fermi GBM Final Real-time Localization
  27. GRB 261024A: BALROG localization (Fermi Trigger 814551785 / GRB 261024683)
  28. GRB 261024A: Fermi GBM Final Real-time Localization
  29. EP261023a: Mondy optical upper limit
  30. EP261015a: VLA non-detection
  31. EP261023a: NOT optical counterpart candidate
  32. EP261023a: Einstein Probe detection of an X-ray transient
  33. GRB 261019A: Insight-HXMT/HE detection
  34. The EP-WXT trigger 01709321472 is likely a flaring star
  35. NuSTAR 261020, a 830s hard X-ray transient
  36. EP261015a: GSP multiband optical follow-up observations
  37. GRB 261017A: SVOM/GRM observation
  38. GRB 261021A: Fermi GBM Final Real-time Localization
  39. GRB 261020B: AstroSat CZTI detection of a short burst
  40. Fermi-LAT Gamma-ray Observations of IceCube-261020A
  41. EP261015a: AZT-20 Assy-Turgen optical observations
  42. GRB 261020A: Fermi GBM Observation
  43. GRB 261017A: SAO RAS optical upper limit
  44. GRB 260903A
  45. EP261015a: Follow-up with the 1.3m DFOT
  46. EP261015a: Terskol Zeiss-2000 optical upper limit
  47. EP261007b: Further EP-FXT follow-up observations
  48. GRB 261017A: COLIBRÍ optical upper limit
  49. IceCube-261020A - IceCube observation of a high-energy neutrino candidate track-like event
  50. GRB 261020A: MAXI GSC detection
  51. GRB 261020A: Fermi GBM Final Real-time Localization
  52. GRB 261019A: Fermi GBM Final Localization
  53. GRB 261017A: Possible Swift/UVOT Detection
  54. GRB 261017A: Luminance-band upper limit from a 28cm telescope in Chengde
  55. EP261015b: NOT Optical Observations
  56. GRB 261017A: J band upper limit by the SYSU 80cm infrared telescope
  57. EP261015c: refined analysis of the EP-FXT observation favors a stellar flare interpretation
  58. GRB 261017A : MITSuME Akeno optical upper limits
  59. GRB 261017A: Nanshan/NEXT optical upper limit
  60. GRB 261017A: Enhanced Swift-XRT position
  61. GRB 261017A: Fermi GBM Observation
  62. GRB261010A: Retraction of Keck/MOSFIRE near-IR source
  63. GRB 261017A: Swift detection of a burst
  64. GRB 261017A: Fermi GBM Final Real-time Localization
  65. EP261015a: Tentative fading of the candidate optical counterpart from the NOT
  66. EP261015b: Refined analysis of EP-FXT observations
  67. EP261015b: J-band upper limit by the SYSU 80cm infrared telescope
  68. EP261015a: refined analysis of EP-FXT observations
  69. EP261015c: J-band upper limit with WINTER
  70. EP261015a: J-band upper limit with WINTER
  71. GRB 261011A: 1.3m DFOT optical upper limit
  72. GRB 261010A: Pan-STARRS z-band imaging and upper limit
  73. EP261015a: SVOM/VT optical observation
  74. EP241111a and EP250125a: Upper limits from SVOM/GRM Observations
  75. GRB 261010A: VLA radio observations
  76. EP261015a: COLIBRÍ optical observations
  77. EP261015c: Einstein Probe detection of a fast X-ray transient
  78. EP261015b: Einstein Probe detection of an X-ray transient
  79. EP261015a: Einstein Probe detection of a fast X-ray transient
  80. EP261015a (WXT 11900947714): Possible optical counterpart from NOT and LCO
  81. The EP-WXT trigger 01709321333 is likely a flaring star
  82. GRB 261010A: ASKAP non-detection of a radio afterglow
  83. GRB 261010A: LBT tentative near-infrared detection
  84. GRB 261011A: SAO RAS and AbAO optical observations
  85. GRB 261010A: Glowbug gamma-ray detection
  86. GRB 261008A: SVOM/GRM observation
  87. GRB 261009A: GECAM-B detection of a burst
  88. EP261006a : MeerKAT radio observations.
  89. GRB 261013A: Fermi GBM Final Real-time Localization
  90. Fermi-LAT Gamma-ray Observations of IceCube-261012A
  91. GRID detection of GRB 261010A
  92. GRB 261011A: GECAM-B observation
  93. GRB 261011B: GECAM-B observation
  94. GRB 261010A: J-band upper limit by the SYSU 80cm infrared telescope
  95. IceCube-260919A: No transient candidates from the Zwicky Transient Facility
  96. GRB 261011A: Enhanced Swift-XRT position
  97. GRB 261010A: a Type I-L (merger-driven) GRB candidate
  98. GRB 261011A: 10.4m GTC spectroscopic redshift (z = 2.407)
  99. IceCube-261012A - IceCube observation of a high-energy neutrino candidate track-like event
  100. GRB 261010A: 10.4m GTC spectroscopy of the galaxy 2" from the afterglow

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