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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"

16178 results found.

  1. ZTF23aaarlti/AT2023avj: Assy continued optical observations
  2. ZTF23aabmzlp/AT2023azs: Mondy and AbAO optical observations
  3. AT2023avj: X-ray Detection with Swift/XRT
  4. ZTF23aabmzlp/AT2023azs: 1.3m DFOT optical observations
  5. ZTF23aaarlti/AT2023avj: VLA radio detection
  6. ZTF23aabmzlp/AT2023azs: Zwicky Transient Facility discovery of a fast optical transient
  7. IceCube-230122A: BOOTES-2/TELMA Optical Upper Limit
  8. AT2023avj ZTF Candidate: Assy optical observations
  9. ZTF and LT Observations of AT2023avj, a Candidate Optical Afterglow
  10. GRB 230123A: LCOGT Optical Upper Limits
  11. GRB 230123A: Swift/UVOT Upper Limits
  12. GRB 230123A: Zadko observatory - Gingin optical observations
  13. GRB 230116D: 3.6m DOT optical upper limit
  14. GRB 230116D: SAO RAS further observations
  15. GRB 230116D: SAO RAS photometry
  16. GRB 230116D: KGO RC-25 optical observations
  17. GRB 230116D: Sintez-Newton/CrAO optical observations
  18. GRB 230116D: LCOGT Optical Upper Limit
  19. GRB 230116D: SAO RAS redshift
  20. GRB 230116D: GIT optical follow-up
  21. GRB 230116D: GIT optical follow-up
  22. GRB 230116D: Sintez-Newton/CrAO optical afterglow detection
  23. GRB 230116D: Nanshan/NEXT optical afterglow detection
  24. IceCube-230112A: BOOTES-4/MET Optical Upper Limit
  25. GRB 221231A: 3.6m DOT optical upper limit
  26. IceCube-221229A: BOOTES-2/TELMA Optical Upper Limit
  27. ZTF22acaruqr/AT2022adzb: Neil Gehrels Swift Observatory X-ray detection
  28. GRB 221226B: LCOGT Optical Upper Limits
  29. GRB 221226B: Swift-UVOT Detection
  30. GRB 221226B: VLT/X-shooter redshift and host galaxy
  31. IceCube-221224A: BOOTES-4/MET Optical Upper Limit
  32. IceCube-221223A: BOOTES-4/MET Optical Observations
  33. GRB 221218A: 3.6m DOT optical upper limit
  34. GRB 221218A: MITSuME Akeno optical upper limits
  35. GRB 221218A: BOOTES-4/MET and OSN optical upper limits
  36. GRB 221218A: KAIT Optical Upper Limit
  37. IceCube-221210A: BOOTES-4/MET and Lijiang 2.4-meter Telescopes Optical Observations
  38. GRB 221216A: Swift/UVOT Upper Limits
  39. GRB 221216A: Zadko observatory - Gingin optical observations
  40. GRB 221216A: Nanshan/NEXT optical upper limits
  41. GRB 221009A: MuSCAT3 observations
  42. Swift/BAT trigger #1143281 is not a GRB
  43. GRB 221202A: VLT/FORS2 Afterglow Discovery
  44. GRB 221202A: LCOGT Optical Upper Limits
  45. GCN: GRB 221201A: Swift/UVOT Upper Limits
  46. Optical polarization observation of GRB 221009A
  47. IceCube-221124A: BOOTES-4/MET and BOOTES-2/TELMA optical upper limit
  48. GRB 221120A: TURBO Optical Upper Limit
  49. GRB 221120A: VIRT Optical Upper Limit
  50. GRB 221120A: Liverpool Telescope Upper Limits
  51. GRB 221120A: Archival PS1 Imaging of Faint Source near XRT position
  52. GRB221120A: Montarrenti Observatory Upper Limit
  53. GRB 221120A: Swift/UVOT Upper Limits
  54. GRB 221120A: LDT Optical Afterglow Candidate
  55. GRB 221120A: GIT upper limits on optical afterglow
  56. GRB 221115B: LCOGT Optical Upper Limits
  57. GRB 221115B : MeerLICHT upper limits
  58. GRB 221110A: VLT/X-shooter redshift
  59. GRB 221110A: LCOGT Optical Afterglow Detection
  60. GRB 221110A: Swift detection of a burst with an optical counterpart
  61. Swift GRB221110.10: Global MASTER-Net OT detection
  62. GRB 221009A: Hubble Space Telescope observations
  63. Correction to GCN 32852 (GRB 221009A: SARA-RM 1m Optical Afterglow Detection)
  64. GRB 221028A: GRANDMA observations
  65. GRB 221027B: GRANDMA observations
  66. GRB 221028A: 1.3m DFOT Optical upper limit
  67. GRB 221028A: NUTTelA-TAO / BSTI Early Optical Limits
  68. GRB 221028A: NUTTelA-TAO / BSTI Early Optical Limits
  69. GRB 221028A: AKO Optical Upper Limit
  70. GRB 221028A: CrAO/ZTSh optical upper limit
  71. GRB 221028A: HCT optical upper limit
  72. GRB 221028A: MITSuME Okayama optical upper limits
  73. GRB 221028A: LCOGT Optical Upper Limits
  74. GRB 221028A: BOOTES-4/MET optical upper limit
  75. GRB 221028A: GIT optical upper limit
  76. GRB 221027B: Swift/UVOT Upper Limits
  77. GRB 221027B: FRAM-ORM and Ondrejov SBT optical limits
  78. GRB 221027B: BOOTES-1 optical upper limit
  79. GRB 221024A: Mondy optical observations
  80. GRB 221009A: SARA-RM 1m Optical Afterglow Detection
  81. GRB 221009A: spectroscopic confirmation of SN in LBT spectra
  82. GRB 221024A: GIT confirmation of the optical afterglow
  83. GRB 221009A: James Webb Space Telescope Observations
  84. GRB 221009A: optical observations, SN photometric evidence
  85. GRB 221009A: 1.3m DFOT Optical Observations
  86. GRB221009A: LBT optical imaging
  87. GRB 221009A: Peak luminosity of the supernova vs. synchrotron afterglow
  88. GRB 221009A: BOAO NIR detections
  89. GRB 221009A X-ray light-curve and the indication of TeV light-curve
  90. GRB 221009A: Continued LDT Afterglow Monitoring
  91. GRB 221009A: Medicina Radio Telescope observations
  92. GRB 221009A: A type I BdHN of exceptional energetics
  93. GRB 221016A: z-band upper limit, possible afterglow brightening
  94. GRB 221016A: LCOGT Optical Afterglow Detection
  95. GRB 221009A: Faulkes Telescope North continued optical afterglow follow-up
  96. GRB 221009A: continued Assy optical afterglow observations, possible SN evidence
  97. GRB 221009A: VLT spectroscopic detection of the host galaxy
  98. GRB 221009A: ATCA detection
  99. GRB 221009A: Large Binocular Telescope Observatory optical afterglow detection
  100. GRB 221009A: Pan-STARRS optical photometry

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