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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"

38349 results found.

  1. GRB260822B: Fermi GBM Final Localization
  2. GRB 260822A: GROWTH-India Telescope Upper Limits
  3. GRB 260822A: GOTO optical upper limit
  4. GRB 260822A: SVOM detection of a short burst
  5. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  6. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  7. IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
  8. GRB 260818B: VLA radio observations
  9. GRB 260818B: SVOM/C-GFT optical upper limit
  10. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  11. The EP-WXT trigger 01709286204 is likely a flaring star
  12. GRB 260820A: Insight-HXMT/HE detection
  13. IceCube-260821A - IceCube observation of a high-energy neutrino candidate track-like event
  14. GRB 260818B: SVOM/GRM observation
  15. EP detected a brightening of LMXB 1ES 1735-26.9
  16. GRB260820A: Fermi GBM Final Real-Time Localization
  17. GRB 260818B: Insight-HXMT detection
  18. GRB 260818B: EP-FXT follow-up observation
  19. GRB 260818A: J-band observations with WINTER
  20. GRB 260818B: SVOM/ECLAIRs refined analysis
  21. GRB 260818A: SVOM/ECLAIRs refined analysis
  22. GRB 260818B: NOT optical upper limits
  23. GRB 260810A: SVOM/GRM observation
  24. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  25. GRB260818A: EP-FXT follow-up observation
  26. GRB 260818B: LCO optical upper limits
  27. GRB 260818B: SVOM detection of a short burst
  28. SVOM trigger sb26081806 is not a GRB
  29. EP260806a: SAO RAS multicolor optical observations
  30. GRB 260818A: LCO optical upper limits
  31. EP260812a: AbAO optical upper limit
  32. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  33. GRB 260810A: Insight-HXMT/HE detection
  34. GRB 260818A: SVOM possible detection of a long and faint GRB
  35. EP260806a: SVOM/ECLAIRs detection through targeted search
  36. EP260806a: NUTTELA-TAO optical observations
  37. The EP-WXT trigger 01709281429 is likely a flaring star
  38. EP260812a: AZT-22 optical upper limit
  39. EP260812b: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.034
  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 260808B: GTC/OSIRIS+ spectroscopic redshift z = 1.295
  47. GRB 260813A: BALROG localization (Fermi Trigger 808341387 / GRB 260813803)
  48. GRB 260813A: Fermi GBM Final Real-time Localization
  49. EP260812a: NOT and Liverpool Telescope upper limits:
  50. EP260812b: Liverpool Telescope observations
  51. EP260812b: GOTO detection of the optical counterpart
  52. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  53. EP260812a: SVOM/C-GFT optical upper limit
  54. EP260812b: COLIBRÍ optical observations
  55. EP260812b: SVOM/VT optical observation
  56. GRB 260808A: SVOM/GRM observation
  57. EP260812b: Einstein Probe detection of an X-ray transient
  58. EP trigger #01709278129 (EP260812b?): NOT optical counterpart
  59. Fermi GBM Sub-Threshold Detection of GRB 260809A
  60. GRB 260810A: Glowbug gamma-ray detection
  61. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
  62. GRB 260810A: AstroSat CZTI detection of a long burst
  63. EP260812a: Einstein Probe detection of an X-ray transient
  64. GRB 260809A: SAO RAS optical observations
  65. GRB 260808B: SAO RAS optical observations
  66. GRB 260808B: SVOM/VT optical re-brightening at day 3
  67. GRB 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
  68. GRB 260806A: CALET Gamma-Ray Burst Monitor detection
  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. EP260809a: VLT/X-shooter spectroscopic redshift z = 3.07
  77. GRB 260806A: Glowbug gamma-ray detection
  78. GRB 260808A: CALET Gamma-Ray Burst Monitor detection
  79. GRB 260805C: CALET Gamma-Ray Burst Monitor detection
  80. GRB 260804A: CALET Gamma-Ray Burst Monitor detection
  81. GRB260809A/EPF_J234751.2+210212: EP-FXT follow-up observation
  82. The EP-WXT trigger 01709278015 is likely a flaring star
  83. GRB 260809A: SVOM/COLIBRÍ (FM-GFT) optical observation
  84. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) optical observation
  85. GRB 260809A: NOT optical observations
  86. GRB260809A: MAO/AZT-22 optical observations
  87. GRB260809A: OHP/T193 optical observations
  88. IceCube-260805A: Upper limits from a search for additional neutrino events in IceCube
  89. GRB 260809A: SVOM/VT optical counterpart
  90. GRB 260808B: J-band upper limit with WINTER
  91. GRB 260808B: SVOM/ECLAIRs refined analysis
  92. EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
  93. GRB 260809A: SVOM detection of a faint burst
  94. GRB 260808B: Liverpool Telescope optical observations
  95. GRB 260808B: NOT optical observations
  96. GRB 260808B: LCO optical observations
  97. GRB 260808A: NuSTAR detection of prompt emission
  98. EP260809a: COLIBRÍ optical observations
  99. EP260809a: OHP/T193 optical observations
  100. GRB260808B: OHP/T193 optical observations

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