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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"

16159 results found.

  1. GRB 240905E: OHP/MISTRAL T193 optical upper limit
  2. GRB 240905E: NOT optical upper limits
  3. GRB 240905E: REM optical/NIR upper limits
  4. GRB 240905E: LCOGT Optical Upper Limit
  5. GRB 240905E: Swift/UVOT Upper Limits
  6. GRB 240905E: SAO RAS optical upper limit
  7. GRB 240825A: Montarrenti Observatory optical follow-up observations
  8. GRB 240905E: Nanshan/HMT optical upper limit
  9. GRB 240819A: Optical upper limits from TESS
  10. GRB 240825A: ATCA Detection of Radio Counterpart
  11. GRB 240825A: Magnitude Correction in SVOM/C-GFT Optical Observations
  12. GRB 240825A: MeerLICHT afterglow detection
  13. GRB 240828A: SAO RAS AS-500(2) optical observations
  14. GRB 240821A: VLT spectroscopic observations
  15. GRB 240825A: TSHAO Optical Upper Limit
  16. GRB240828B: REM optical/NIR upper limits
  17. GRB 240828B: AbAO optical upper limit
  18. GRB 240825A: SOAR observations
  19. GRB 240828B: Mephisto optical upper limit
  20. GRB 240828B: GRANDMA Optical Upper Limit
  21. GRB 240825A: MeerKAT detection
  22. GRB 240828B: GMG Optical Upper Limit
  23. GRB 240828A: KAIT continued optical observations
  24. GRB 240828B: GWAC-F50A optical upper limit
  25. GRB 240828B: SVOM/C-GFT optical upper limit
  26. GRB 240828B: SAO RAS optical upper limit
  27. GRB 240828B: KAIT optical upper limit
  28. GRB 240828A: SAO RAS optical observations
  29. GRB 240828A: KAIT Optical Afterglow Candidate
  30. GRB 240825A: SVOM/VT optical detection
  31. GRB 240825A: further SAO RAS optical observations
  32. GRB 240825A: iTelescope optical observations
  33. Fermi GRB 240828A: Bassano Bresciano Observatory upper limit
  34. GRB 240825A: Upper limits from a neutrino search with IceCube
  35. GRB 240819A as a likely X-Ray Flash
  36. GRB 240821A: PRIME near-infrared observations
  37. GRB 240825A: VLA detection
  38. SVOM GRB 240821A: optical afterglow discovery
  39. GRB 240828B : Detection of a possible very soft X-ray transient by SVOM/ECLAIRs
  40. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  41. GRB 240825A: ALMA detection
  42. GRB 240825A: SAO RAS optical observations
  43. GRB 240824A: GIT optical upper limit
  44. GRB 240825A: TNG optical photometry and spectroscopy
  45. GRB 240825A: NUTTelA-TAO / BSTI Optical Limits
  46. GRB 240825A: GMG Continued Optical Observation on the Second Night
  47. GRB 240824B: Ondrejov D50 optical limit
  48. GRB 240825A: KAIT optical observations
  49. GRB 240825A: PRIME near-infrared detection
  50. GRB 240825A : MISTRAL/T193 OHP optical follow-up of the afterglow
  51. GRB 240825A: AKO Optical Follow-Up Observations
  52. GRB 240825A: REM detection of the optical/NIR afterglow
  53. GRB 240825A: VLT/X-shooter redshift
  54. GRB 240825A: SVOM/C-GFT optical observations
  55. GRB 240825A: Montarrenti Observatory optical observations
  56. GRB 240825A: MASTER optical counterpart observation
  57. GRB 240825A: LCO optical observations
  58. GRB 240824B: KAIT optical upper limit
  59. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  60. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  61. GRB 240824B: NOT optical upper limit
  62. GRB 240825A: GMG Optical Observation
  63. GRB 240825A: 1.6m Mephisto multi-band detection
  64. GRB 240825A: AKO Optical Afterglow Detection
  65. GRB 240825A: Skynet Optical Afterglow observations
  66. GRB 240825A: Nanshan/HMT optical afterglow observations
  67. GRB 240825A: Swift detection of a burst with a bright optical counterpart
  68. GRB 240824A: SVOM/C-GFT optical upper limit
  69. GRB 240824A: Swift/UVOT Upper Limits
  70. GRB 240824A: Retraction of GCN 37255
  71. GRB240824A: GRANDMA/TAROT-TCA Upper Limit
  72. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  73. GRB 240824A: KAIT optical upper limit
  74. GRB 240824A: Skynet Optical Afterglow Discovery
  75. GRB 240824A: Swift detection of a burst
  76. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  77. GRB 240821A: Colibri Optical Upper Limit
  78. GRB 240821A: REM optical/NIR upper limits
  79. GRB 240821A: LCO optical observations
  80. GRB 240821A: JinShan optical upper limits
  81. GRB 240809A: Mondy and AbAO Optical Observations
  82. GRB 240821A: SVOM/VT follow-up and optical upper limit
  83. GRB 240821A: GMG Optical Upper Limit
  84. EP240801a: Keck/LRIS spectroscopic redshift confirmation
  85. GRB 240821A: GRANDMA/LesMakes-T60 Upper Limit
  86. GRB 240821A : a likely short GRB detected by SVOM/ECLAIRs
  87. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  88. EP240820a: TRT optical upper limit
  89. GRB 240819A: KAIT optical upper limit
  90. GRB 240819A : an X-ray transient detected by SVOM/ECLAIRs
  91. GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
  92. EP240816b: Liverpool Telescope optical follow-up observations
  93. EP240816a: BOOTES-6/DPRT optical upper limit
  94. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  95. GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
  96. EP240816b: KAIT optical upper limit
  97. EP240816b: TRT optical upper limit
  98. EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
  99. GRB 240809A: ATA radio non-detection
  100. GRB 240809A: VLA detection

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