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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"

20501 results found.

  1. EP260131a: COLIBRÍ observations of slow optical fading
  2. EP260131a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  3. EP260131a: VLT/X-shooter spectroscopic redshift z = 0.937
  4. EP260131a: NOT early detection of the counterpart in "rapid response mode"
  5. EP260131a: COLIBRÍ optical observations of the counterpart
  6. EP260131a: Einstein Probe detection of an X-ray transient
  7. EP260128a / GRB 260128A: COLIBRÍ optical upper limit
  8. GRB 260128B: LCO optical upper limits
  9. GRB 260128B: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  10. EP260128a: J band upper limit by SYSU 80cm infrared telescope
  11. GRB 260128B: SVOM detection of a burst through offline search
  12. GRB 260127B: Swift-XRT observations
  13. GRB 260127A: INASAN-Kislovodsk, SAO RAS, and Terskol K-800 optical observations
  14. EP260128a: NOT optical counterpart candidate
  15. EP260128a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  16. EP260128a: Liverpool Telescope optical observations and possible counterpart
  17. EP260128a: LCO optical upper limits
  18. EP260128a: Einstein Probe detection of an X-ray transient
  19. IceCube-260125A: Upper limits from a search for additional neutrino events in IceCube
  20. GRB 260127A: COLIBRÍ optical observations
  21. EP260126a: Seimei/TriCCS optical upper limit
  22. GRB 260127A : MITSuME Akeno optical afterglow candidate detection
  23. GRB 260127A: SVOM/C-GFT optical observations
  24. GRB 260127A: Enhanced Swift-XRT position
  25. GRB 260127A: LCO optical afterglow discovery
  26. GRB 260127A: Swift detection of a burst
  27. GRB 260125A: Swift-XRT observations
  28. EP260126a: Optical upper limit with Kinder observations
  29. EP260126a: Liverpool Telescope optical upper limits
  30. EP260126a: Further NOT optical upper limits
  31. EP260126a: COLIBRÍ optical upper limits
  32. EP260126a: NOT optical observations
  33. EP260126a: Einstein Probe detection of a fast X-ray transient
  34. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  35. GRB 251222A: SVOM/ECLAIRs refined analysis
  36. GRB 260125A: GOTO candidate optical counterpart
  37. GRB 260114A: SVOM/VT optical upper limits
  38. GRB 260120B: SVOM/GRM observation
  39. GRB 260120B: AstroSat CZTI detection
  40. EP260119a: Assy AZT-20 optical observations
  41. EP260119a: Mondy and SAO RAS optical upper limits
  42. EP260119a: Xinglong optical upper limit
  43. EP260116a: COLIBRÍ further observations
  44. GRB 251122A / EP251122a: VLT/X-shooter host redshift z = 1.765
  45. GRB 260120B: Fermi GBM Observation
  46. EP260105a: GTC/HiPERCAM optical observations
  47. GRB 260120B: Swift/UVOT Detection
  48. GRB 260120B: COLIBRÍ optical upper limits
  49. GRB 260120B: Enhanced Swift-XRT position
  50. GRB 260120B: SVOM/C-GFT optical counterpart detection
  51. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  52. GRB 260120B: Swift detection of a burst
  53. EP260119A: Mondy I-Band Observations
  54. GRB 260114A: Swift/UVOT Upper Limits
  55. EP260119a: Liverpool Telescope optical follow-up observations
  56. GRB 251202A: further radio observations with the VLA
  57. EP260119A: GTC/OSIRIS+ spectroscopic redshift z = 5.47
  58. EP260119a: KAIT optical observations
  59. EP260119a: SVOM/VT optical observation
  60. EP260119a: NOT optical observations
  61. EP260119a: SAO RAS optical observations
  62. EP260116a: COLIBRÍ detection of a fading optical source
  63. GRB 251208D: SVOM/ECLAIRs refined analysis
  64. GRB 251208D: SVOM/ECLAIRs refined analysis
  65. GRB 260117A: Swift-XRT afterglow detection
  66. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  67. EP260119a: LCO optical observations
  68. GRB 260117A: ZTSh optical upper limit
  69. EP260119a: COLIBRÍ optical counterpart candidate
  70. GRB 260110A: SVOM detection of a burst through offline search
  71. EP260119a: EP-WXT detection of a fast X-ray transient
  72. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  73. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  74. Swift trigger on the HMXB 1A 1118-61
  75. GRB 260117A: SVOM/C-GFT upper limit
  76. GRB 260117A: SVOM detection of a long faint burst
  77. EP 260116a: COLIBRÍ optical upper limit
  78. Swift triggered on the HMXB 1A 1118-61
  79. FRB 20251229A: COLIBRÍ further inspection of the updated localization
  80. EP260116a: Liverpool Telescope upper limits
  81. EP260116A: 1.3m DFOT optical upper limit
  82. GRB 260114A: VLT/MUSE spectroscopic observations
  83. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  84. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  85. EP260116a: Xinglong optical upper limit
  86. EP260116a: Einstein Probe detection of an X-ray transient
  87. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  88. GRB 251222A: radio detection with the VLA
  89. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  90. GRB 260114A: Swift-XRT refined Analysis
  91. GRB 260114A: 6 GHz VLA observations
  92. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  93. GRB 260114A : MITSuME Akeno optical upper limits
  94. GRB 260114A: COLIBRÍ optical upper limits
  95. GRB 260114A: TNG NIR upper limit
  96. GRB 260114A: NOT optical observations
  97. GRB 260114A: SVOM/GRM observation of a short burst
  98. GRB 260114A: Mondy optical observations
  99. GRB 260114A: GMG Optical Observation
  100. GRB 260114A: Swift detection of a short burst

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