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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"

19700 results found.

  1. GRB 210222B: 1.3m DFOT Optical upper limit
  2. GRB 210226A: Swift detection of a burst
  3. GRB 210222B: REM observations of the optical/NIR afterglow
  4. GRB 210222B: MITSuME Akeno optical upper limits
  5. GRB 210222B: Zeiss-1000 of Koshka observatory, optical observations
  6. GRB 210222B: VIRT optical detection
  7. GRB 210222B: Swift-XRT refined Analysis
  8. GRB 210222B: Swift/UVOT Detection
  9. GRB 210218A: Swift/UVOT observations
  10. GRB 210217A: Swift/UVOT Detection
  11. GRB 210222B: MASTER OT observation
  12. GRB 210222B: NEXT early optical afterglow observations
  13. GRB 210222B: GOTO confirmation of afterglow detection (correction to GCN29548)
  14. GRB 210222B: Liverpool Telescope optical detection
  15. GRB 210222B: GOTO confirmation of afterglow detection
  16. GRB 210222B: Swift detection of a burst with an optical counterpart
  17. GRB 210212A: Lowell Discovery Telescope observations
  18. GRB 210217A: Liverpool Telescope First Hour Observations
  19. GRB 210218A: MITSuME Akeno optical upper limits
  20. GRB 210218A: NEXT optical upper limit
  21. ZTF21aakruew/AT2021cwd: GROND observations
  22. GRB 210212A: REM early-time optical/NIR upper limits
  23. GRB 210217A: Enhanced Swift-XRT position
  24. GRB 210217A: NEXT early optical afterglow observations
  25. GRB 210212A: Mondy optical observations
  26. GRB 210217A: Swift detection of a burst with an optical counterpart
  27. GRB 210208A: 1.3m DFOT Optical upper limit
  28. Swift Trigger 1033144: Detection of SGR 1830-0645
  29. GRB 210211A: ePESSTO+ NTT optical observations
  30. GRB 210212B: Swift ToO observations
  31. IPN triangulation of GRB 210212B (consistent with ZTF21aakruew/AT2021cwd)
  32. GRB 210212A: 1.3m DFOT Optical upper limit
  33. GRB 210212A: Gemini South optical observations
  34. IceCube-210210A: Four Candidate Optical Counterparts from DECam Observations
  35. Swift Trigger 1032350: Detection of SGR 1830-0645
  36. GRB 210212A: Possible host galaxy counterpart with the NOT
  37. GRB 210212A: MITSuME Akeno optical upper limits
  38. GRB 210212A: Swift/UVOT Upper Limits
  39. GRB 210212A: Enhanced Swift-XRT position
  40. GRB 210212A: Swift detection of a burst
  41. GRB 210207B: GECAM detection
  42. GRB 210211A: Swift/UVOT Detection
  43. GRB 210211A: Swift-BAT refined analysis
  44. GRB 210210A as a BdHN II
  45. Swift-XRT observations of IceCube-210210A
  46. GRB 210211A: Enhanced Swift-XRT position
  47. GRB 210211A: MASTER optical observation of REM OT
  48. GRB 210211A: REM optical/NIR afterglow detection
  49. GRB 210211A: Swift detection of a burst
  50. IceCube-210210A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  51. Swift GRB 210209A: Global MASTER-Net observations report
  52. GRB 210210A: Swift/UVOT Detection
  53. GRB 210112A: LBT host detection and correction to GCN 29319 (CAHA observations)
  54. GRB 210209A: MITSuME Akeno optical upper limits
  55. GRB 210209A: Swift/UVOT Upper Limits
  56. GRB 210208A: GIT optical upper limit
  57. GRB 210210A: Enhanced Swift-XRT position
  58. GRB 210210A: MASTER afterglow observation
  59. GRB 210210A: Swift detection of a burst with an optical counterpart
  60. GRB 210209A: Enhanced Swift-XRT position
  61. GRB 210209A: Swift detection of a burst
  62. GRB 210104A: LBT observations
  63. GRB 210204A (ZTF21aagwbjr/AT2021buv): continued Mondy optical observations
  64. GRB 210207B: Swift/UVOT Detection
  65. GRB 210204A: LBT observations and jet break
  66. GRB 210207B: LCO Optical Afterglow Detection
  67. GRB 210208A: A long GRB detected by INTEGRAL
  68. GRB 210207B: AbAO optical upper limit
  69. GRB 210207B: Enhanced Swift-XRT position
  70. GRB 210207B: Swift detection of a burst with a bright optical counterpart
  71. GRB 210204A: Optical Observations from HCT
  72. GRB 210204A / ZTF21aagwbjr: Swift-XRT observations
  73. GRB 210204A: Swift ToO observations
  74. IPN triangulation of GRB 210204A
  75. GRB 210205A: MITSuME Ishigaki optical observation
  76. GRB 210205B: AGILE/MCAL detection of a burst
  77. GRB 210205A: Swift/UVOT Upper Limits
  78. GRB 210205A: Nanshan/NEXT optical upper limit
  79. GRB 210205A: Enhanced Swift-XRT position
  80. GRB 210205A: Swift detection of a burst
  81. GRB 210204: Fermi GBM observation
  82. Recent activity of SGR 1935+2154 as observed by CGBM
  83. GRB 210131A: GECAM detection
  84. IPN triangulation of a bright burst from SGR 1935+2154
  85. GRB 210121A: GECAM detection
  86. GRB 210120A : 1.3m DFOT optical observations
  87. GRB 210120A(MASTER OT J105242.66+152355.0 / AT2021axc): Mondy optical observations
  88. GRB 210104A: 3.6m DOT optical upper limit
  89. GRB 210112A: 3.6m DOT optical detection
  90. GRB 210119A (Swift J1851.2-6148): Swift-BAT refined analysis
  91. GECAM detection of a short GRB 210119A or a new SGR candidate Swift J1851.2-6148
  92. ZTF21aaeyldq: GROND observations
  93. GRB 210119A: Fermi GBM observation
  94. ZTF21aaeyldq: LBT near-infrared observations
  95. ZTF21aaeyldq: KPED observations
  96. Correction to GCN 29288: NuEm-210111A: No counterpart candidates in INTEGRAL SPI-ACS observation
  97. GRB 201221D: near-infrared observation with LBT
  98. ZTF21aaeyldq: NOT optical observations
  99. ZTF21aaeyldq: Lowell Discovery Telescope observations
  100. GRB 201015A: evidence of supernova in LBT spectra

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