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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"

16162 results found.

  1. GRB 230827B / GRB 230827256: Fermi GBM Observation
  2. Subject: GRB230826A: Swift/UVOT upper limits
  3. GRB 230827.256: AKO Optical follow-up of ZTF23abaanxz (AT 2023qxj)
  4. Swift J1727.8-1613 (GRB 230824A): Osservatorio Astronomico "Nastro Verde" optical observations
  5. GRB 230827.256 : GIT optical follow-up of ZTF23abaanxz/AT2023qxj
  6. AT 2023qxj: ZTF discovery of the likely afterglow of Fermi GRB 230827256
  7. Swift J1727.8-1613 (GRB 230824A): Leavitt Observatory optical observations
  8. GRB 230826A: Mondy optical observations
  9. Swift J1727.8-1613 (GRB 230824A): GAD Observatory La Spezia - optical observations
  10. Swift J1727.8-1613 (GRB 230824A): Bassano Bresciano Observatory optical observations
  11. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
  12. GRB 230824A: AKO Optical Afterglow Candidate
  13. GRB 230824A is likely a Galactic Transient: Swift J1727.8-1613
  14. GRB 230812B: Assy optical observations, possible SN rise
  15. GRB 230812B: SAO RAS RC-500 and Zeiss-1000 observations
  16. GRB 20230818A: GIT optical upper limit
  17. GRB 230812B : GRANDMA/Kilonova-Catcher optical afterglow detection and upper limits
  18. GRB 230812B: GIT Confirmation of SN rise
  19. GRB 230818A: Nickel and KAIT telescope optical observations
  20. GRB 230818A: AKO Upper Limit
  21. GRB 230818A: Tautenburg observations
  22. GRB 230818A: Bassano Bresciano Observatory optical observations
  23. GRB 230818A: KGO RC-25 optical observations
  24. GRB 230818A: Swift/UVOT Detection
  25. GRB 230818A: NOT photometry and spectroscopy
  26. GRB 230818A: GOTO optical afterglow detection
  27. Swift GRB230818.98: Global MASTER-Net OT detection
  28. GRB 230816A: SVOM/C-GFT optical detection
  29. GRB 230812B: SAO RAS optical observations
  30. GRB 230816A: Osservatorio Astronomico "Nastro Verde" optical observations
  31. GRB 230812B: optical photometry from Konkoly
  32. GRB 230812B: SAO RAS optical observations
  33. GRB230816A: Possible host and GIT detection of optical counterpart
  34. GRB 230816A: Tautenburg observations
  35. GRB 230816A: AKO Optical Observations
  36. GRB 230816A: TShAO and Assy optical observations
  37. GRB 230816A: SAO RAS optical observations
  38. GRB 230816A: Nanshan/HMT optical afterglow detection
  39. GRB 230815A: SOAR/Goodman follow-up imaging
  40. GRB230815A: Swift/UVOT upper limits
  41. GRB 230812B: GAD Observatory optical observations (upper limit)
  42. GRB 230812B: iTelescope optical upper limit
  43. GRB 230812B: continued SAO RAS optical observation
  44. GRB230815A: BOOTES-6/DPRT optical upper limit
  45. GRB 230812B: Tautenburg observations
  46. GRB 230812B: continued AbAO optical afterglow observations
  47. GRB 230812B: Optical observaions from Rozhen Observatory
  48. GRB 230812B: Further Bassano Bresciano Observatory optical observations
  49. GRB 230812B: further SAO RAS optical observations
  50. GRB 230812B: CrAO ZTSh optical observations
  51. GRB 230812B: Koshka Zeiss-1000 optical observations
  52. GRB 230812B: GIT optical follow-up
  53. GRB 230812B: Leavitt Observatory optical observations
  54. GRB 230812B : optical observations from Observatoire de Haute-Provence
  55. GRB 230812B: Bassano Bresciano Observatory optical observations
  56. GRB 230812B: Faulkes Telescope North optical afterglow follow-up
  57. GRB 230812B: Osservatorio Astronomico "Nastro Verde" optical observation
  58. GRB 230812B: OASDG optical observations
  59. GRB 230812B: AbAO optical observations
  60. GRB 230812B: Montarrenti Observatory optical observations
  61. GRB 230812B: SAO RAS optical observations
  62. GRB 230812B: Detected Optical Afterglow Candidate
  63. GRB 230812B: GMG - GRANDMA observations
  64. GRB 230812: Swift/UVOT Detection
  65. GOTO confirmation and possible host galaxy of GRB230812B optical afterglow
  66. GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
  67. Fermi GRB 230812B: MASTER optical counterpart
  68. GRB 230812B: KAIT Optical Afterglow Candidate
  69. GRB 230812B: Fermi GBM detection of an extremely bright GRB
  70. GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
  71. ZTF23aaoohpy/AT2023lcr: JWST observations consistent with the presence of a supernova
  72. GRB 230805B : MITSuME Akeno optical upper limits
  73. GRB 230805B : OHP/T193 optical upper limit
  74. GRB 230805B: Swift/UVOT Upper Limits
  75. GRB 230805B: Bassano Bresciano observatory upper limit
  76. GRB 230805B: BOOTES-6/DPRT optical upper limit and 1.5m OSN detection
  77. GRB 230805B: NOT optical afterglow confirmation
  78. GRB 230805B: SAO RAS optical observations
  79. GRB 230802A: Swift/UVOT Upper Limits
  80. GRB 230802A: BOOTES-5/JGT optical upper limit
  81. GRB 230723B: MITSuME Ishigaki optical observation
  82. GRB 230728A: BOOTES-1 optical upper limit
  83. GRB 230728A: LCOGT Optical Upper Limit
  84. GRB 230728A: Swift/UVOT Upper Limits
  85. GRB 230728A: NOT optical observations and possible host galaxy
  86. GRB 230723B: Further CAHA observations and host galaxy detection
  87. GRB 230723B: MITSuME Akeno optical afterglow candidate detection
  88. GRB 230723B: GAD Observatory, La Spezia, Italy upper limit
  89. GRB 230723B: Osservatorio Astronomico Nastro Verde upper limit
  90. GRB 230723B: Montarrenti Observatory upper limit
  91. GRB 230723B: Optical afterglow candidate from CAHA
  92. GRB 230723B: Bassano Bresciano Observatory upper limit
  93. GRB 230723B: Optical limit from CAHA
  94. GRB 230723B: Swift/UVOT Upper Limits
  95. LIGO/Virgo/KAGRA S230627c: GECKO optical follow-up observations of host galaxy candidates and ZTF23aaptsuy/AT2023lxu
  96. GRB 230328B: LBT detection of the likely host galaxy
  97. LIGO/Virgo/KAGRA S230627c: observations of ZTF23aaptsuy/AT2023lx in AbAO observatory
  98. GRB 230628E: Swift/UVOT Detection
  99. AT2023lcr (ATLAS23msn/ZTF23aaoohpy): ALMA 100 GHz Detection
  100. GRB 230628E - VLT spectroscopic observations

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