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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"

15742 results found.

  1. GRB 240825A: SOAR observations
  2. GRB 240828B: Mephisto optical upper limit
  3. GRB 240828B: GRANDMA Optical Upper Limit
  4. GRB 240825A: MeerKAT detection
  5. GRB 240828B: GMG Optical Upper Limit
  6. GRB 240828A: KAIT continued optical observations
  7. GRB 240828B: GWAC-F50A optical upper limit
  8. GRB 240828B: SVOM/C-GFT optical upper limit
  9. GRB 240828B: SAO RAS optical upper limit
  10. GRB 240828B: KAIT optical upper limit
  11. GRB 240828A: SAO RAS optical observations
  12. GRB 240828A: KAIT Optical Afterglow Candidate
  13. GRB 240825A: SVOM/VT optical detection
  14. GRB 240825A: further SAO RAS optical observations
  15. GRB 240825A: iTelescope optical observations
  16. Fermi GRB 240828A: Bassano Bresciano Observatory upper limit
  17. GRB 240825A: Upper limits from a neutrino search with IceCube
  18. GRB 240819A as a likely X-Ray Flash
  19. GRB 240821A: PRIME near-infrared observations
  20. GRB 240825A: VLA detection
  21. SVOM GRB 240821A: optical afterglow discovery
  22. GRB 240828B : Detection of a possible very soft X-ray transient by SVOM/ECLAIRs
  23. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  24. GRB 240825A: ALMA detection
  25. GRB 240825A: SAO RAS optical observations
  26. GRB 240824A: GIT optical upper limit
  27. GRB 240825A: TNG optical photometry and spectroscopy
  28. GRB 240825A: NUTTelA-TAO / BSTI Optical Limits
  29. GRB 240825A: GMG Continued Optical Observation on the Second Night
  30. GRB 240824B: Ondrejov D50 optical limit
  31. GRB 240825A: KAIT optical observations
  32. GRB 240825A: PRIME near-infrared detection
  33. GRB 240825A : MISTRAL/T193 OHP optical follow-up of the afterglow
  34. GRB 240825A: AKO Optical Follow-Up Observations
  35. GRB 240825A: REM detection of the optical/NIR afterglow
  36. GRB 240825A: VLT/X-shooter redshift
  37. GRB 240825A: SVOM/C-GFT optical observations
  38. GRB 240825A: Montarrenti Observatory optical observations
  39. GRB 240825A: MASTER optical counterpart observation
  40. GRB 240825A: LCO optical observations
  41. GRB 240824B: KAIT optical upper limit
  42. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  43. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  44. GRB 240824B: NOT optical upper limit
  45. GRB 240825A: GMG Optical Observation
  46. GRB 240825A: 1.6m Mephisto multi-band detection
  47. GRB 240825A: AKO Optical Afterglow Detection
  48. GRB 240825A: Skynet Optical Afterglow observations
  49. GRB 240825A: Nanshan/HMT optical afterglow observations
  50. GRB 240825A: Swift detection of a burst with a bright optical counterpart
  51. GRB 240824A: SVOM/C-GFT optical upper limit
  52. GRB 240824A: Swift/UVOT Upper Limits
  53. GRB 240824A: Retraction of GCN 37255
  54. GRB240824A: GRANDMA/TAROT-TCA Upper Limit
  55. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  56. GRB 240824A: KAIT optical upper limit
  57. GRB 240824A: Skynet Optical Afterglow Discovery
  58. GRB 240824A: Swift detection of a burst
  59. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  60. GRB 240821A: Colibri Optical Upper Limit
  61. GRB 240821A: REM optical/NIR upper limits
  62. GRB 240821A: LCO optical observations
  63. GRB 240821A: JinShan optical upper limits
  64. GRB 240809A: Mondy and AbAO Optical Observations
  65. GRB 240821A: SVOM/VT follow-up and optical upper limit
  66. GRB 240821A: GMG Optical Upper Limit
  67. EP240801a: Keck/LRIS spectroscopic redshift confirmation
  68. GRB 240821A: GRANDMA/LesMakes-T60 Upper Limit
  69. GRB 240821A : a likely short GRB detected by SVOM/ECLAIRs
  70. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  71. EP240820a: TRT optical upper limit
  72. GRB 240819A: KAIT optical upper limit
  73. GRB 240819A : an X-ray transient detected by SVOM/ECLAIRs
  74. GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
  75. EP240816b: Liverpool Telescope optical follow-up observations
  76. EP240816a: BOOTES-6/DPRT optical upper limit
  77. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  78. GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
  79. EP240816b: KAIT optical upper limit
  80. EP240816b: TRT optical upper limit
  81. EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
  82. GRB 240809A: ATA radio non-detection
  83. GRB 240809A: VLA detection
  84. GRB 240811A: Bassano Bresciano Observatory upper limit
  85. GRB 240811A: Swift/UVOT Upper Limits
  86. EP240801a: Assy-Turgen optical observations
  87. GRB 240811A: LCOGT Optical Upper Limit
  88. GRB 240811A: Upper limits with Mephisto
  89. GRB240809A: Liverpool Telescope optical follow-up observations
  90. GRB 240809A: REM detection of the optical afterglow
  91. GRB 240809A: Bassano Bresciano Observatory optical observations
  92. GRB 240809A: Conclusive redshift from VLT
  93. GRB 240809A: KAIT optical observations
  94. GRB 240809A: GIT afterglow observations
  95. GRB 240809A: Tentative redshift from NOT
  96. GRB 240809A: JinShan optical observations
  97. GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
  98. GRB 240809A: Swift detection of a burst with a bright optical counterpart
  99. EP240807a: STEP/T80S optical limits
  100. EP-WXT trigger 01709018832: KAIT optical observations of the star flare

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