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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"

23402 results found.

  1. GRB 260914A: SVOM detection of a burst
  2. GRB 260913A: SVOM trigger sb26091302 is not an astrophysical event
  3. GRB 260913A: SVOM/C-GFT optical upper limit
  4. GRB 260913A: SVOM detection of a faint burst
  5. GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
  6. GRB 260907A: SVOM/GRM observation
  7. GRB 260909A: CrAO and AbAO optical upper limits
  8. GRB 260909A: SVOM/ECLAIRs refined analysis
  9. GRB 260910B: GOTO tentative optical counterpart candidates
  10. GRB 260909A: KAIT optical upper limit
  11. GRB 260903A: Swift-XRT observations
  12. GRB 260909A: OHP/T193 z-band upper limit
  13. GRB 260909A: VLT optical and near-infrared upper limits
  14. EP260806a: NOEMA detection
  15. EP260623a: NOEMA detections
  16. GRB 260909A: SVOM/VT optical upper limits
  17. GRB 260909A: Mondy optical observations and afterglow candidate
  18. GRB 260909A: Xinglong 2.16m optical upper limit
  19. GRB 260909A: SVOM/C-GFT optical upper limit
  20. GRB 260909A: SVOM detection of a burst
  21. EP Alert 260908.60: Global MASTER-Net observations report
  22. GRB 260907A: Glowbug gamma-ray detection of a likely short burst
  23. GRB 260903A: SAO RAS optical upper limit
  24. GRB 260903A: J-band upper limit with WINTER
  25. GRB260903A: Liverpool Telescope optical observations
  26. GRB 260903A: SAO RAS optical observations
  27. EP260903a: EP-WXT detection of a fast X-ray transient
  28. GRB 260830A: Insight-HXMT/HE detection
  29. GRB 260903A: OHP/T193 optical afterglow detection
  30. NuSTAR Transient 260828: SOAR Optical Upper Limits
  31. GRB 260903A: LCO optical counterpart detection
  32. EP260901a: SVOM/VT optical upper limits
  33. GRB 260829A: SVOM/GRM observation
  34. GRB 260818A: ATCA detection of a candidate radio counterpart
  35. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  36. NuSTAR Transient 260828: LCO Optical Upper Limits
  37. EP260901a: EP-WXT detection of a fast X-ray transient
  38. GRB 260829A: AstroSat CZTI detection
  39. GRB 260831B: EP-FXT follow-up observation
  40. GRB 260831B: LCO optical upper limits
  41. EP260830a: EP-WXT detection of a fast X-ray transient
  42. GRB 260827A: SVOM/GRM observation
  43. NuSTAR 260828: a 1100s hard X-ray transient
  44. GRB 260831B: SVOM detection of a possible burst
  45. IPN triangulation of GRB 260829A
  46. GRB 260827A: Glowbug gamma-ray detection
  47. GRB 260825A: SVOM/GRM observation of a long burst
  48. GRB 260818B: Further EP-FXT observation
  49. GRB 260818B: VLT optical and nIR observations
  50. GRB 260818B: TNG NIR observations
  51. GRB 260818B: 6 GHz VLA observations
  52. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  53. GRB 260808B: SAO RAS observations of the optical rebrightening
  54. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  55. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  56. EP260822a: EP-FXT non-detection and upper limit
  57. GRB 260822A: GOTO optical counterpart detection
  58. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  59. EP260822a: Einstein Probe detection of a fast X-ray transient
  60. GRB 260822A: LCO optical upper limits
  61. GRB 260822A: GROWTH-India Telescope Upper Limits
  62. GRB 260818B: VLA radio observations
  63. GRB 260818B: SVOM/C-GFT optical upper limit
  64. EP detected a brightening of LMXB 1ES 1735-26.9
  65. GRB 260818A: J-band observations with WINTER
  66. GRB 260818B: NOT optical upper limits
  67. GRB 260810A: SVOM/GRM observation
  68. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  69. GRB 260818B: LCO optical upper limits
  70. EP260806a: SAO RAS multicolor optical observations
  71. GRB 260818A: LCO optical upper limits
  72. EP260812a: AbAO optical upper limit
  73. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  74. EP260806a: NUTTELA-TAO optical observations
  75. EP260812a: AZT-22 optical upper limit
  76. EP260806a: WFST optical observations
  77. EP260812b: Optical upper limit with Kinder
  78. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  79. GRB 260808B: Liverpool Telescope further optical observations
  80. GRB 260808B: GTC/OSIRIS+ spectroscopic redshift z = 1.295
  81. EP260812a: NOT and Liverpool Telescope upper limits:
  82. EP260812b: Liverpool Telescope observations
  83. EP260812b: GOTO detection of the optical counterpart
  84. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  85. EP260812a: SVOM/C-GFT optical upper limit
  86. EP260812b: COLIBRÍ optical observations
  87. EP260812b: SVOM/VT optical observation
  88. GRB 260808A: SVOM/GRM observation
  89. EP260812b: Einstein Probe detection of an X-ray transient
  90. EP trigger #01709278129 (EP260812b?): NOT optical counterpart
  91. GRB 260810A: Glowbug gamma-ray detection
  92. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
  93. GRB 260810A: AstroSat CZTI detection of a long burst
  94. EP260812a: Einstein Probe detection of an X-ray transient
  95. GRB 260809A: SAO RAS optical observations
  96. GRB 260808B: SAO RAS optical observations
  97. GRB 260808B: SVOM/VT optical re-brightening at day 3
  98. EP260806a: MAO/AZT-22 optical observations
  99. GRB260808B: MAO/AZT-22 optical observations
  100. GRB 250607A: SVOM/ECLAIRs detection through offline targeted search

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