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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"

2797 results found.

  1. GRB 230216A: Zadko observatory - Gingin optical observations
  2. GRB 230205A: SUBARU HSC pre-imaging for host galaxy search
  3. GRB 230205A: possible host galaxy detection with the Schmidt - Asiago telescope
  4. ZTF23aabmzlp/AT2023azs: Neil Gehrels Swift Observatory X-ray observations
  5. GRB 230204B: Swift-XRT afterglow detection
  6. GRB 230205A: OHP/T193 optical observations
  7. GRB 230204A/Swift J1552.8-5055: LCOGT Optical Counterpart Candidate
  8. GRB 230204A: Swift detection of a possible burst (or possible transient Swift J1552.8-5055)
  9. GRB 221216A: Swift-BAT refined analysis
  10. IceCube-230201A - IceCube observation of a high-energy neutrino candidate track-like event
  11. ZTF23aabmzlp/AT2023azs: Zwicky Transient Facility discovery of a fast optical transient
  12. IceCube-230122A - IceCube observation of a high-energy neutrino candidate track-like event
  13. IceCube-230112A - IceCube observation of a high-energy neutrino candidate track-like event
  14. IceCube-221229A - IceCube observation of a high-energy neutrino candidate track-like event
  15. ZTF22acaruqr/AT2022adzb: Neil Gehrels Swift Observatory X-ray detection
  16. IceCube-221224A - IceCube observation of a high-energy neutrino candidate track-like event
  17. IceCube-221223A - IceCube observation of a high-energy neutrino candidate track-like event
  18. IceCube-221216A - IceCube observation of a high-energy neutrino candidate track-like event
  19. IceCube-221210A - IceCube observation of a high-energy neutrino candidate track-like event
  20. IceCube-221124A - IceCube observation of a high-energy neutrino candidate track-like event
  21. GRB 221120A: Archival PS1 Imaging of Faint Source near XRT position
  22. GRB 221120A: Swift detection of a likely short burst
  23. IceCube-221104A - IceCube observation of a high-energy neutrino candidate track-like event
  24. GRB 221024A: Swift-BAT refined analysis
  25. GRB 221009A: Analysis of the initial episode using data of GBM/Fermi and SPI-ACS/INTEGRAL
  26. GRB 221016A: z-band upper limit, possible afterglow brightening
  27. GRB 221009A: continued Assy optical afterglow observations, possible SN evidence
  28. MAXI GRB 221006A: Redshifts of the possible host galaxies
  29. Afterglow limits of GRB 221006A from OHP
  30. GRB 221009A: Swift detected transient may be GRB
  31. IceCube-220928A - IceCube observation of a high-energy neutrino candidate track-like event
  32. IceCube-220907A: Classification of AT2022oyn as a Type Ia supernova
  33. GRB 220921A: MASTER OT inside Fermi-LAT error-box
  34. Fermi-LAT gamma-ray observations of IceCube-220918A and detection of a new gamma-ray source, Fermi J0502.5+0037
  35. IceCube-220918A - IceCube observation of a high-energy neutrino candidate track-like event
  36. IceCube-220907A - IceCube observation of a high-energy neutrino candidate track-like event
  37. GRB 220831A: DECam detection of a possible optical counterpart
  38. IceCube-220822A: Classification of AT2022saw as a Type Ia supernova
  39. IceCube-220822A: One Candidate Counterpart from the Zwicky Transient Facility
  40. IceCube-220822A - IceCube observation of a high-energy neutrino candidate track-like event
  41. GRB 220813A: VLT optical observations and possible host galaxy
  42. Swift/BAT Trigger 1116172 (=GRB 220714A) is not a real astrophysical event
  43. GRB 220714A: Possible Swift detection of a burst
  44. IceCube-220624A: Classification of AT2022nit as a type Ia supernova and AT2021bei as an AGN
  45. IceCube-220629A - IceCube observation of a high-energy neutrino candidate track-like event
  46. Konus-Wind detection of GRB 220627A
  47. IceCube-220624A: One Candidate Counterpart from Swift/XRT follow up observations
  48. Swift XRT observations of WISEA J145820.77+412101.9 / IceCube 220624A
  49. GRB 220627A: Fermi GBM Detection of a possible Lensed or Ultra-long GRB
  50. IceCube-220627A - IceCube observation of a high-energy neutrino candidate track-like event
  51. GRB 220623A: Swift-BAT refined analysis
  52. IceCube-220624A - IceCube observation of a high-energy neutrino candidate track-like event
  53. GRB 220611A: Gemini Ks counterpart detection
  54. GRB 220611A: Swift-BAT refined analysis
  55. GRB 220527A: VLT/X-shooter spectroscopic redshift
  56. GRB 220521A: classification and detection by SPI-ACS/INTEGRAL
  57. IceCube-220524A - IceCube observation of a high-energy neutrino candidate track-like event
  58. IceCube-220513A - IceCube observation of a high-energy neutrino candidate track-like event
  59. IceCube-220509A - IceCube observation of a high-energy neutrino candidate track-like event
  60. IceCube-220501A - IceCube observation of a high-energy neutrino candidate track-like event
  61. IceCube-220425A: MASTER: flaring blazar TXS 1742-078 as the possible neutrino source candidate
  62. IceCube-220424A - IceCube observation of a high-energy neutrino candidate track-like event
  63. IceCube-220421A - IceCube observation of a high-energy neutrino candidate track-like event
  64. GRB 220408A: redshift lower limit estimating
  65. IceCube-220405A - IceCube observation of a high-energy neutrino candidate track-like event
  66. IceCube-220405A - IceCube observation of a high-energy neutrino candidate track-like event
  67. GRB 220403B: Swift detection of a burst with an optical counterpart
  68. IceCube-220317A - IceCube observation of a high-energy neutrino candidate track-like event
  69. ZTF22aabjpxh/AT2022cva (GRB 220219B): continued optical observations, possible photometric evidence of SN
  70. CALET Gamma-Ray Burst Monitor detection of GRB 220308A and its possible precursor
  71. GRB 220306B: Mondy optical observations, confirmation afterglow candidate
  72. GRB 220306B: AbAO optical observations, possible afterglow candidate
  73. IceCube-220306A - IceCube observation of a high-energy neutrino candidate track-like event
  74. IceCube-220304A - IceCube observation of a high-energy neutrino candidate track-like event
  75. Tev Blazar as possible optical counterpart of the high-energy neutrino IceCube-220303A
  76. IceCube-220303A - IceCube observation of a high-energy neutrino candidate track-like event
  77. IceCube-220225A - IceCube observation of a high-energy neutrino candidate track-like event
  78. IceCube Alert 220220.60:NuEm-220220A: MASTER optical possible counterpart
  79. ZTF22aabjpxh/AT2022cva: ZTF Discovery of a Rapidly Fading Transient with a Likely Long-GRB Counterpart
  80. IceCube-220221A - IceCube observation of a high-energy neutrino candidate track-like event
  81. ZTF22aaajecp/AT2022cmc: Keck DEIMOS Redshift
  82. GRB 220211A: redshift lower limit estimating
  83. GRB 210919A: SPI-ACS/INTEGRAL observation and evaluation of Ep
  84. IceCube-220205B - IceCube observation of a high-energy neutrino candidate track-like event
  85. IceCube-220205A - IceCube observation of a high-energy neutrino candidate track-like event
  86. IceCube-220202A: IceCube observation of a high-energy neutrino candidate track-like event
  87. Swift currently in safe hold with science slews disabled
  88. IceCube-220115A - IceCube observation of a high-energy neutrino candidate track-like event
  89. Konus-Wind detection of GRB 220101A (correction to GCN 31433)
  90. GRB 211227A: A possible short GRB with extended emission at z = 0.228?
  91. IceCube-211216B - IceCube observation of a high-energy neutrino candidate track-like event
  92. IceCube-211216A - IceCube observation of a high-energy neutrino candidate track-like event
  93. GRB 211211A - Gemini K-band detection
  94. GRB 211211A: redshift estimation and SPI-ACS/INTEGRAL detection
  95. GRB 211130A: MeerLICHT identification of possible afterglow candidate
  96. IceCube-211208A - IceCube observation of a high-energy neutrino candidate track-like event
  97. Swift Trigger 1086826 (possible GRB 211203A) is likely not an astrophysical event
  98. GRB 211106A: HST Observations
  99. IceCube-211125A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  100. IceCube-211125A: IceCube observation of a high-energy neutrino candidate track-like event

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