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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"

2632 results found.

  1. Fermi GBM-230619: A soft subthreshold candidate potentially associated with a subthreshold LIGO/Virgo compact binary merger candidate
  2. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Swift/UVOT detection
  3. AT2023lcr: Pan-STARRS & ATLAS Observations
  4. ZTF23aaoohpy/AT2023lcr: Keck/LRIS spectroscopy and redshift
  5. LIGO/Virgo/KAGRA S230615az: GOTO candidate counterparts
  6. IceCube-230603A - IceCube observation of a high-energy neutrino candidate track-like event
  7. IceCube-230524A - IceCube observation of a high-energy neutrino candidate track-like event
  8. LIGO/Virgo/KAGRA S230518h: ATLAS observations of the skymap
  9. GRB 230512A: Kitab possible afterglow candidate
  10. IceCube-230511A: IceCube observation of a high-energy neutrino candidate
  11. GRB 230506C: TSHAO possible afterglow candidate
  12. IceCube-230506A: IceCube observation of a high-energy neutrino candidate
  13. GRB 230430A: A short GRB from a neutron star merger
  14. GRB 230420A: Lowell Discovery Telescope Optical Detection
  15. GRB 230420A: Swift-BAT refined analysis
  16. IceCube-230416A: IceCube observation of a high-energy neutrino candidate
  17. GRB 230414B (correction GRB name in the GCN 33615): Mondy optical afterglow candidate
  18. GRB 230328B: redshift lower limit estimating
  19. GRB 230307A: JWST NIRSpec observations, possible higher redshift
  20. GRB 230307A: short mininum variability timescale compatible with a merger origin
  21. IceCube-230405A: IceCube observation of a high-energy neutrino candidate
  22. Fermi-LAT gamma-ray observations of IceCube-230401A and detection of Fermi J0030.2+0005
  23. IceCube-230401A: IceCube observation of a high-energy neutrino candidate
  24. GRB 230307A: INTEGRAL upper limit on Hard X-ray afterglow
  25. GRB 230307A: SOAR/Goodman detection of the possible host galaxy
  26. GRB 230307A: ATLAS information on the ULTRACAM optical afterglow candidate
  27. GRB 230307A: Possible optical afterglow
  28. Solar Orbiter STIX observation of GRB 230307A
  29. GRB 230307A: GECAM detection of an extremely bright burst
  30. IceCube-230306A - IceCube observation of a high-energy neutrino candidate
  31. GRB 230228A: Miryang Arirang Astronomical Observatory (MAAO) 0.7-m telescope optical upper limit
  32. IceCube-230220A - IceCube observation of a high-energy neutrino candidate
  33. IceCube-230217A - IceCube observation of a high-energy neutrino candidate track-like event
  34. GRB 230216A: Swift-BAT refined analysis
  35. GRB 230216A: AKO Upper Limit
  36. GRB 230216A: Zadko observatory - Gingin optical observations
  37. GRB 230205A: SUBARU HSC pre-imaging for host galaxy search
  38. GRB 230205A: possible host galaxy detection with the Schmidt - Asiago telescope
  39. ZTF23aabmzlp/AT2023azs: Neil Gehrels Swift Observatory X-ray observations
  40. GRB 230204B: Swift-XRT afterglow detection
  41. GRB 230205A: OHP/T193 optical observations
  42. GRB 230204A/Swift J1552.8-5055: LCOGT Optical Counterpart Candidate
  43. GRB 230204A: Swift detection of a possible burst (or possible transient Swift J1552.8-5055)
  44. GRB 221216A: Swift-BAT refined analysis
  45. IceCube-230201A - IceCube observation of a high-energy neutrino candidate track-like event
  46. ZTF23aabmzlp/AT2023azs: Zwicky Transient Facility discovery of a fast optical transient
  47. IceCube-230122A - IceCube observation of a high-energy neutrino candidate track-like event
  48. IceCube-230112A - IceCube observation of a high-energy neutrino candidate track-like event
  49. IceCube-221229A - IceCube observation of a high-energy neutrino candidate track-like event
  50. ZTF22acaruqr/AT2022adzb: Neil Gehrels Swift Observatory X-ray detection
  51. IceCube-221224A - IceCube observation of a high-energy neutrino candidate track-like event
  52. IceCube-221223A - IceCube observation of a high-energy neutrino candidate track-like event
  53. IceCube-221216A - IceCube observation of a high-energy neutrino candidate track-like event
  54. IceCube-221210A - IceCube observation of a high-energy neutrino candidate track-like event
  55. IceCube-221124A - IceCube observation of a high-energy neutrino candidate track-like event
  56. GRB 221120A: Archival PS1 Imaging of Faint Source near XRT position
  57. GRB 221120A: Swift detection of a likely short burst
  58. IceCube-221104A - IceCube observation of a high-energy neutrino candidate track-like event
  59. GRB 221024A: Swift-BAT refined analysis
  60. GRB 221009A: Analysis of the initial episode using data of GBM/Fermi and SPI-ACS/INTEGRAL
  61. GRB 221016A: z-band upper limit, possible afterglow brightening
  62. GRB 221009A: continued Assy optical afterglow observations, possible SN evidence
  63. MAXI GRB 221006A: Redshifts of the possible host galaxies
  64. Afterglow limits of GRB 221006A from OHP
  65. GRB 221009A: Swift detected transient may be GRB
  66. IceCube-220928A - IceCube observation of a high-energy neutrino candidate track-like event
  67. IceCube-220907A: Classification of AT2022oyn as a Type Ia supernova
  68. GRB 220921A: MASTER OT inside Fermi-LAT error-box
  69. Fermi-LAT gamma-ray observations of IceCube-220918A and detection of a new gamma-ray source, Fermi J0502.5+0037
  70. IceCube-220918A - IceCube observation of a high-energy neutrino candidate track-like event
  71. IceCube-220907A - IceCube observation of a high-energy neutrino candidate track-like event
  72. GRB 220831A: DECam detection of a possible optical counterpart
  73. IceCube-220822A: Classification of AT2022saw as a Type Ia supernova
  74. IceCube-220822A: One Candidate Counterpart from the Zwicky Transient Facility
  75. IceCube-220822A - IceCube observation of a high-energy neutrino candidate track-like event
  76. GRB 220813A: VLT optical observations and possible host galaxy
  77. Swift/BAT Trigger 1116172 (=GRB 220714A) is not a real astrophysical event
  78. GRB 220714A: Possible Swift detection of a burst
  79. IceCube-220624A: Classification of AT2022nit as a type Ia supernova and AT2021bei as an AGN
  80. IceCube-220629A - IceCube observation of a high-energy neutrino candidate track-like event
  81. Konus-Wind detection of GRB 220627A
  82. IceCube-220624A: One Candidate Counterpart from Swift/XRT follow up observations
  83. Swift XRT observations of WISEA J145820.77+412101.9 / IceCube 220624A
  84. GRB 220627A: Fermi GBM Detection of a possible Lensed or Ultra-long GRB
  85. IceCube-220627A - IceCube observation of a high-energy neutrino candidate track-like event
  86. GRB 220623A: Swift-BAT refined analysis
  87. IceCube-220624A - IceCube observation of a high-energy neutrino candidate track-like event
  88. GRB 220611A: Gemini Ks counterpart detection
  89. GRB 220611A: Swift-BAT refined analysis
  90. GRB 220527A: VLT/X-shooter spectroscopic redshift
  91. GRB 220521A: classification and detection by SPI-ACS/INTEGRAL
  92. IceCube-220524A - IceCube observation of a high-energy neutrino candidate track-like event
  93. IceCube-220513A - IceCube observation of a high-energy neutrino candidate track-like event
  94. IceCube-220509A - IceCube observation of a high-energy neutrino candidate track-like event
  95. IceCube-220501A - IceCube observation of a high-energy neutrino candidate track-like event
  96. IceCube-220425A: MASTER: flaring blazar TXS 1742-078 as the possible neutrino source candidate
  97. IceCube-220424A - IceCube observation of a high-energy neutrino candidate track-like event
  98. IceCube-220421A - IceCube observation of a high-energy neutrino candidate track-like event
  99. GRB 220408A: redshift lower limit estimating
  100. IceCube-220405A - IceCube observation of a high-energy neutrino candidate track-like event

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