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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"

26292 results found.

  1. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  2. GRB 260808B: SAO RAS observations of the optical rebrightening
  3. EP Alert 260820.31: Global MASTER-Net observations report
  4. GRB 260807A: EP-FXT follow-up observations
  5. GRB 260822A: SVOM/ECLAIRs refined analysis
  6. GRB 260809A: SVOM/ECLAIRs refined analysis
  7. IceCube-Cascade 260824A: Upper limits from a search for additional neutrino events in IceCube
  8. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  9. GRB 260822A: EP/FXT follow-up observations
  10. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  11. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  12. EP260822a: EP-FXT non-detection and upper limit
  13. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  14. EP260822a: Einstein Probe detection of a fast X-ray transient
  15. GRB 260822A: LCO optical upper limits
  16. The EP-WXT trigger 01709287395 is likely a flaring star
  17. GRB 260822A: GROWTH-India Telescope Upper Limits
  18. GRB 260822A: SVOM detection of a short burst
  19. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  20. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  21. IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
  22. GRB 260818B: SVOM/C-GFT optical upper limit
  23. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  24. The EP-WXT trigger 01709286204 is likely a flaring star
  25. GRB 260818B: SVOM/GRM observation
  26. EP detected a brightening of LMXB 1ES 1735-26.9
  27. GRB 260818B: EP-FXT follow-up observation
  28. GRB 260818A: J-band observations with WINTER
  29. GRB 260818B: SVOM/ECLAIRs refined analysis
  30. GRB 260818A: SVOM/ECLAIRs refined analysis
  31. GRB 260818B: NOT optical upper limits
  32. GRB 260810A: SVOM/GRM observation
  33. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  34. GRB260818A: EP-FXT follow-up observation
  35. GRB 260818B: LCO optical upper limits
  36. GRB 260818B: SVOM detection of a short burst
  37. EP260806a: SAO RAS multicolor optical observations
  38. GRB 260818A: LCO optical upper limits
  39. EP260812a: AbAO optical upper limit
  40. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  41. GRB 260818A: SVOM possible detection of a long and faint GRB
  42. EP260806a: SVOM/ECLAIRs detection through targeted search
  43. EP260806a: NUTTELA-TAO optical observations
  44. The EP-WXT trigger 01709281429 is likely a flaring star
  45. EP260812a: AZT-22 optical upper limit
  46. EP260806a: WFST optical observations
  47. The EP-WXT trigger 01709280562 is likely a flaring star
  48. EP260812b: Optical upper limit with Kinder
  49. The EP-WXT trigger 01709279838 is likely a flaring star
  50. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  51. GRB 260808B: Liverpool Telescope further optical observations
  52. GRB 260813A: BALROG localization (Fermi Trigger 808341387 / GRB 260813803)
  53. EP260812a: NOT and Liverpool Telescope upper limits:
  54. EP260812b: Liverpool Telescope observations
  55. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  56. EP260812a: SVOM/C-GFT optical upper limit
  57. EP260812b: COLIBRÍ optical observations
  58. EP260812b: SVOM/VT optical observation
  59. GRB 260808A: SVOM/GRM observation
  60. EP260812b: Einstein Probe detection of an X-ray transient
  61. EP trigger #01709278129 (EP260812b?): NOT optical counterpart
  62. GRB 260810A: Glowbug gamma-ray detection
  63. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
  64. GRB 260810A: AstroSat CZTI detection of a long burst
  65. EP260812a: Einstein Probe detection of an X-ray transient
  66. GRB 260809A: SAO RAS optical observations
  67. GRB 260808B: SAO RAS optical observations
  68. GRB 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
  69. GRB 260808A: GECAM-B observation
  70. GRB 260807A: SVOM/ECLAIRs refined analysis
  71. EP260806a: MAO/AZT-22 optical observations
  72. IceCube-260807A: Upper limits from a search for additional neutrino events in IceCube
  73. GRB260808B: MAO/AZT-22 optical observations
  74. GRB 250607A: SVOM/ECLAIRs detection through offline targeted search
  75. GRB 260809A: J-band upper limit with WINTER
  76. GRB 260806A: Glowbug gamma-ray detection
  77. GRB260809A/EPF_J234751.2+210212: EP-FXT follow-up observation
  78. The EP-WXT trigger 01709278015 is likely a flaring star
  79. GRB 260809A: SVOM/COLIBRÍ (FM-GFT) optical observation
  80. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) optical observation
  81. GRB 260809A: NOT optical observations
  82. GRB260809A: MAO/AZT-22 optical observations
  83. GRB260809A: OHP/T193 optical observations
  84. IceCube-260805A: Upper limits from a search for additional neutrino events in IceCube
  85. EP260809a: J-band upper limit with WINTER
  86. GRB 260808B: J-band upper limit with WINTER
  87. GRB 260808B: SVOM/ECLAIRs refined analysis
  88. EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
  89. GRB 260809A: SVOM detection of a faint burst
  90. GRB 260808B: Liverpool Telescope optical observations
  91. GRB 260808B: NOT optical observations
  92. GRB 260808B: LCO optical observations
  93. EP260809a: COLIBRÍ optical observations
  94. EP260809a: LCO optical observation
  95. EP260809a: OHP/T193 optical observations
  96. GRB260808B: OHP/T193 optical observations
  97. GRB 260808B / EPF_J230056.0+082842: EP-FXT follow-up observation
  98. EP260809a: Einstein Probe detection of an X-ray transient
  99. GRB 260808B: SVOM/VT optical candidate from VHF data ( localization correction for GCN 45317 )
  100. GRB 260808B: SVOM/VT optical candidate from VHF data

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