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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"

26486 results found.

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

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