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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

16152 results found.

  1. GRB 230228A: Miryang Arirang Astronomical Observatory (MAAO) 0.7-m telescope optical upper limit
  2. GRB 230217A: VLT/FORS2 optical observations and candidate counterpart
  3. GRB 230216A Mondy Observations
  4. GRB 230217A: Swift/UVOT Upper Limits
  5. GRB 230216A: Swift/UVOT Upper Limits
  6. GRB 230217A: Gemini South optical upper limits
  7. GRB 230217A: Gemini-South Optical Observation
  8. IceCube-230217A: BOOTES-4/MET Optical Observations
  9. GRB 230216A: SVOM/C-GFT optical upper limit
  10. GRB 230204B: Lowell Discovery Telescope Observations
  11. GRB 230216A: Zadko observatory - Gingin optical observations
  12. GRB 230204B: ATCA radio detection
  13. GRB 230205A: 6 GHz VLA observations
  14. GRB 230204B: MASTER early OT detection
  15. ZTF23aabmzlp/AT2023azs: Neil Gehrels Swift Observatory X-ray observations
  16. GRB 230204B: LCOGT Optical Upper Limits
  17. GRB 230204B: Swift/UVOT Upper Limits
  18. GRB 230205A: Swift/UVOT Upper Limits
  19. GRB 230205A: LCOGT Optical Upper Limits
  20. GRB 230204B: Swift-XRT afterglow detection
  21. GRB 230204B: 3.6m DOT optical observation
  22. GRB 230205A: SVOM/C-GFT optical upper limit
  23. GRB 230205A: OHP/T193 optical observations
  24. GRB 230204B: VLT/X-shooter redshift
  25. GRB 230204B: ATLAS detection of the optical afterglow and a projected location in a nearby galaxy group
  26. GRB 230205A: BOOTES-5/JGT early optical upper limit
  27. IceCube-230201A: BOOTES-4/MET Optical Upper Limits
  28. GRB 230204B: GIT discovery of the likely optical afterglow
  29. GRB 230204A: Swift/UVOT Upper Limits
  30. GRB 230204A/Swift J1552.8-5055: LCOGT Optical Counterpart Candidate
  31. GRB 230201B: TURBO Optical Upper Limits
  32. ZTF23aabmzlp/AT2023azs: Lulin 1m LOT optical observations
  33. ZTF23aabmzlp/AT2023azs: VLA radio detection
  34. ZTF23aaarlti/AT2023avj: AMI-LA radio detection
  35. ZTF23aabmzlp/AT2023azs: AMI-LA radio upper limit
  36. ZTF23aabmzlp/AT2023azs: LCOGT Optical Detection
  37. ZTF23aaarlti/AT2023avj: Assy continued optical observations
  38. ZTF23aabmzlp/AT2023azs: Mondy and AbAO optical observations
  39. AT2023avj: X-ray Detection with Swift/XRT
  40. ZTF23aabmzlp/AT2023azs: 1.3m DFOT optical observations
  41. ZTF23aaarlti/AT2023avj: VLA radio detection
  42. ZTF23aabmzlp/AT2023azs: Zwicky Transient Facility discovery of a fast optical transient
  43. IceCube-230122A: BOOTES-2/TELMA Optical Upper Limit
  44. AT2023avj ZTF Candidate: Assy optical observations
  45. ZTF and LT Observations of AT2023avj, a Candidate Optical Afterglow
  46. GRB 230123A: LCOGT Optical Upper Limits
  47. GRB 230123A: Swift/UVOT Upper Limits
  48. GRB 230123A: Zadko observatory - Gingin optical observations
  49. GRB 230116D: 3.6m DOT optical upper limit
  50. GRB 230116D: SAO RAS further observations
  51. GRB 230116D: SAO RAS photometry
  52. GRB 230116D: KGO RC-25 optical observations
  53. GRB 230116D: Sintez-Newton/CrAO optical observations
  54. GRB 230116D: LCOGT Optical Upper Limit
  55. GRB 230116D: SAO RAS redshift
  56. GRB 230116D: GIT optical follow-up
  57. GRB 230116D: GIT optical follow-up
  58. GRB 230116D: SAO RAS observations of OT brightening
  59. GRB 230116D: Sintez-Newton/CrAO optical afterglow detection
  60. GRB 230116D: Nanshan/NEXT optical afterglow detection
  61. IceCube-230112A: BOOTES-4/MET Optical Upper Limit
  62. GRB 221231A: 3.6m DOT optical upper limit
  63. IceCube-221229A: BOOTES-2/TELMA Optical Upper Limit
  64. ZTF22acaruqr/AT2022adzb: Neil Gehrels Swift Observatory X-ray detection
  65. GRB 221226B: LCOGT Optical Upper Limits
  66. GRB 221226B: Swift-UVOT Detection
  67. GRB 221226B: VLT/X-shooter redshift and host galaxy
  68. IceCube-221224A: BOOTES-4/MET Optical Upper Limit
  69. IceCube-221223A: BOOTES-4/MET Optical Observations
  70. GRB 221218A: 3.6m DOT optical upper limit
  71. GRB 221218A: MITSuME Akeno optical upper limits
  72. GRB 221218A: BOOTES-4/MET and OSN optical upper limits
  73. GRB 221218A: KAIT Optical Upper Limit
  74. IceCube-221210A: BOOTES-4/MET and Lijiang 2.4-meter Telescopes Optical Observations
  75. GRB 221216A: Swift/UVOT Upper Limits
  76. GRB 221216A: Zadko observatory - Gingin optical observations
  77. GRB 221216A: Nanshan/NEXT optical upper limits
  78. GRB 221009A: MuSCAT3 observations
  79. Swift/BAT trigger #1143281 is not a GRB
  80. GRB 221202A: VLT/FORS2 Afterglow Discovery
  81. GRB 221202A: LCOGT Optical Upper Limits
  82. GCN: GRB 221201A: Swift/UVOT Upper Limits
  83. Optical polarization observation of GRB 221009A
  84. IceCube-221124A: BOOTES-4/MET and BOOTES-2/TELMA optical upper limit
  85. GRB 221120A: TURBO Optical Upper Limit
  86. GRB 221120A: VIRT Optical Upper Limit
  87. GRB 221120A: Liverpool Telescope Upper Limits
  88. GRB 221120A: Archival PS1 Imaging of Faint Source near XRT position
  89. GRB221120A: Montarrenti Observatory Upper Limit
  90. GRB 221120A: Swift/UVOT Upper Limits
  91. GRB 221120A: LDT Optical Afterglow Candidate
  92. GRB 221120A: GIT upper limits on optical afterglow
  93. GRB 221115B: LCOGT Optical Upper Limits
  94. GRB 221115B : MeerLICHT upper limits
  95. GRB 221110A: VLT/X-shooter redshift
  96. GRB 221110A: LCOGT Optical Afterglow Detection
  97. GRB 221110A: Swift detection of a burst with an optical counterpart
  98. Swift GRB221110.10: Global MASTER-Net OT detection
  99. GRB 221009A: Hubble Space Telescope observations
  100. Correction to GCN 32852 (GRB 221009A: SARA-RM 1m Optical Afterglow Detection)

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