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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"

26499 results found.

  1. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  2. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  3. GRB 260818B: Further EP-FXT observation
  4. GRB 260818B: VLT optical and nIR observations
  5. GRB 260818B: TNG NIR observations
  6. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  7. GRB 260818B: 6 GHz VLA observations
  8. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  9. GRB 260808B: SAO RAS observations of the optical rebrightening
  10. EP Alert 260820.31: Global MASTER-Net observations report
  11. GRB 260807A: EP-FXT follow-up observations
  12. GRB 260822A: SVOM/ECLAIRs refined analysis
  13. GRB 260809A: SVOM/ECLAIRs refined analysis
  14. IceCube-Cascade 260824A: Upper limits from a search for additional neutrino events in IceCube
  15. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  16. GRB 260822A: EP/FXT follow-up observations
  17. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  18. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  19. EP260822a: EP-FXT non-detection and upper limit
  20. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  21. EP260822a: Einstein Probe detection of a fast X-ray transient
  22. GRB 260822A: LCO optical upper limits
  23. The EP-WXT trigger 01709287395 is likely a flaring star
  24. GRB 260822A: GROWTH-India Telescope Upper Limits
  25. GRB 260822A: SVOM detection of a short burst
  26. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  27. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  28. IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
  29. GRB 260818B: SVOM/C-GFT optical upper limit
  30. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  31. The EP-WXT trigger 01709286204 is likely a flaring star
  32. GRB 260818B: SVOM/GRM observation
  33. EP detected a brightening of LMXB 1ES 1735-26.9
  34. GRB 260818B: EP-FXT follow-up observation
  35. GRB 260818A: J-band observations with WINTER
  36. GRB 260818B: SVOM/ECLAIRs refined analysis
  37. GRB 260818A: SVOM/ECLAIRs refined analysis
  38. GRB 260818B: NOT optical upper limits
  39. GRB 260810A: SVOM/GRM observation
  40. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  41. GRB260818A: EP-FXT follow-up observation
  42. GRB 260818B: LCO optical upper limits
  43. GRB 260818B: SVOM detection of a short burst
  44. EP260806a: SAO RAS multicolor optical observations
  45. GRB 260818A: LCO optical upper limits
  46. EP260812a: AbAO optical upper limit
  47. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  48. GRB 260818A: SVOM possible detection of a long and faint GRB
  49. EP260806a: SVOM/ECLAIRs detection through targeted search
  50. EP260806a: NUTTELA-TAO optical observations
  51. The EP-WXT trigger 01709281429 is likely a flaring star
  52. EP260812a: AZT-22 optical upper limit
  53. EP260806a: WFST optical observations
  54. The EP-WXT trigger 01709280562 is likely a flaring star
  55. EP260812b: Optical upper limit with Kinder
  56. The EP-WXT trigger 01709279838 is likely a flaring star
  57. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  58. GRB 260808B: Liverpool Telescope further optical observations
  59. GRB 260813A: BALROG localization (Fermi Trigger 808341387 / GRB 260813803)
  60. EP260812a: NOT and Liverpool Telescope upper limits:
  61. EP260812b: Liverpool Telescope observations
  62. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  63. EP260812a: SVOM/C-GFT optical upper limit
  64. EP260812b: COLIBRÍ optical observations
  65. EP260812b: SVOM/VT optical observation
  66. GRB 260808A: SVOM/GRM observation
  67. EP260812b: Einstein Probe detection of an X-ray transient
  68. EP trigger #01709278129 (EP260812b?): NOT optical counterpart
  69. GRB 260810A: Glowbug gamma-ray detection
  70. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
  71. GRB 260810A: AstroSat CZTI detection of a long burst
  72. EP260812a: Einstein Probe detection of an X-ray transient
  73. GRB 260809A: SAO RAS optical observations
  74. GRB 260808B: SAO RAS optical observations
  75. GRB 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
  76. GRB 260808A: GECAM-B observation
  77. GRB 260807A: SVOM/ECLAIRs refined analysis
  78. EP260806a: MAO/AZT-22 optical observations
  79. IceCube-260807A: Upper limits from a search for additional neutrino events in IceCube
  80. GRB260808B: MAO/AZT-22 optical observations
  81. GRB 250607A: SVOM/ECLAIRs detection through offline targeted search
  82. GRB 260809A: J-band upper limit with WINTER
  83. GRB 260806A: Glowbug gamma-ray detection
  84. GRB260809A/EPF_J234751.2+210212: EP-FXT follow-up observation
  85. The EP-WXT trigger 01709278015 is likely a flaring star
  86. GRB 260809A: SVOM/COLIBRÍ (FM-GFT) optical observation
  87. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) optical observation
  88. GRB 260809A: NOT optical observations
  89. GRB260809A: MAO/AZT-22 optical observations
  90. GRB260809A: OHP/T193 optical observations
  91. IceCube-260805A: Upper limits from a search for additional neutrino events in IceCube
  92. EP260809a: J-band upper limit with WINTER
  93. GRB 260808B: J-band upper limit with WINTER
  94. GRB 260808B: SVOM/ECLAIRs refined analysis
  95. EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
  96. GRB 260809A: SVOM detection of a faint burst
  97. GRB 260808B: Liverpool Telescope optical observations
  98. GRB 260808B: NOT optical observations
  99. GRB 260808B: LCO optical observations
  100. EP260809a: COLIBRÍ optical observations

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