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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').

2445 results found.

  1. GRB 230805B: SAO RAS optical observations
  2. GRB 230728A: NOT optical observations and possible host galaxy
  3. IceCube-230727A - IceCube observation of a high-energy neutrino candidate track-like event
  4. IceCube-230724A - IceCube observation of a high-energy neutrino candidate track-like event
  5. IceCube-230725A - IceCube observation of a high-energy neutrino candidate track-like event
  6. GRB 230723B: Optical afterglow candidate from CAHA
  7. GRB 230723B: Optical limit from CAHA
  8. Swift Trigger 1178410: possible GRB 230709A
  9. IceCube-230708A - IceCube observation of a high-energy neutrino candidate track-like event
  10. IceCube-230707B - IceCube observation of a high-energy neutrino candidate track-like event
  11. IceCube-230707A - IceCube observation of a high-energy neutrino candidate track-like event
  12. GRB 230628E - VLT spectroscopic observations
  13. LIGO/Virgo/KAGRA S230627c: ATLAS information on the ZTF candidates
  14. Fermi GBM-230619: A soft subthreshold candidate potentially associated with a subthreshold LIGO/Virgo compact binary merger candidate
  15. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Swift/UVOT detection
  16. AT2023lcr: Pan-STARRS & ATLAS Observations
  17. ZTF23aaoohpy/AT2023lcr: Keck/LRIS spectroscopy and redshift
  18. LIGO/Virgo/KAGRA S230615az: GOTO candidate counterparts
  19. IceCube-230603A - IceCube observation of a high-energy neutrino candidate track-like event
  20. IceCube-230524A - IceCube observation of a high-energy neutrino candidate track-like event
  21. LIGO/Virgo/KAGRA S230518h: ATLAS observations of the skymap
  22. GRB 230512A: Kitab possible afterglow candidate
  23. IceCube-230511A: IceCube observation of a high-energy neutrino candidate
  24. GRB 230506C: TSHAO possible afterglow candidate
  25. IceCube-230506A: IceCube observation of a high-energy neutrino candidate
  26. GRB 230430A: A short GRB from a neutron star merger
  27. GRB 230420A: Lowell Discovery Telescope Optical Detection
  28. GRB 230420A: Swift-BAT refined analysis
  29. IceCube-230416A: IceCube observation of a high-energy neutrino candidate
  30. GRB 230414B (correction GRB name in the GCN 33615): Mondy optical afterglow candidate
  31. GRB 230328B: redshift lower limit estimating
  32. GRB 230307A: JWST NIRSpec observations, possible higher redshift
  33. GRB 230307A: short mininum variability timescale compatible with a merger origin
  34. IceCube-230405A: IceCube observation of a high-energy neutrino candidate
  35. Fermi-LAT gamma-ray observations of IceCube-230401A and detection of Fermi J0030.2+0005
  36. IceCube-230401A: IceCube observation of a high-energy neutrino candidate
  37. GRB 230307A: INTEGRAL upper limit on Hard X-ray afterglow
  38. GRB 230307A: SOAR/Goodman detection of the possible host galaxy
  39. GRB 230307A: ATLAS information on the ULTRACAM optical afterglow candidate
  40. GRB 230307A: Possible optical afterglow
  41. Solar Orbiter STIX observation of GRB 230307A
  42. GRB 230307A: GECAM detection of an extremely bright burst
  43. IceCube-230306A - IceCube observation of a high-energy neutrino candidate
  44. GRB 230228A: Miryang Arirang Astronomical Observatory (MAAO) 0.7-m telescope optical upper limit
  45. IceCube-230220A - IceCube observation of a high-energy neutrino candidate
  46. IceCube-230217A - IceCube observation of a high-energy neutrino candidate track-like event
  47. GRB 230216A: Swift-BAT refined analysis
  48. GRB 230216A: AKO Upper Limit
  49. GRB 230216A: Zadko observatory - Gingin optical observations
  50. GRB 230205A: SUBARU HSC pre-imaging for host galaxy search
  51. GRB 230205A: possible host galaxy detection with the Schmidt - Asiago telescope
  52. ZTF23aabmzlp/AT2023azs: Neil Gehrels Swift Observatory X-ray observations
  53. GRB 230204B: Swift-XRT afterglow detection
  54. GRB 230205A: OHP/T193 optical observations
  55. GRB 230204A/Swift J1552.8-5055: LCOGT Optical Counterpart Candidate
  56. GRB 230204A: Swift detection of a possible burst (or possible transient Swift J1552.8-5055)
  57. GRB 221216A: Swift-BAT refined analysis
  58. IceCube-230201A - IceCube observation of a high-energy neutrino candidate track-like event
  59. ZTF23aabmzlp/AT2023azs: Zwicky Transient Facility discovery of a fast optical transient
  60. IceCube-230122A - IceCube observation of a high-energy neutrino candidate track-like event
  61. IceCube-230112A - IceCube observation of a high-energy neutrino candidate track-like event
  62. IceCube-221229A - IceCube observation of a high-energy neutrino candidate track-like event
  63. ZTF22acaruqr/AT2022adzb: Neil Gehrels Swift Observatory X-ray detection
  64. IceCube-221224A - IceCube observation of a high-energy neutrino candidate track-like event
  65. IceCube-221223A - IceCube observation of a high-energy neutrino candidate track-like event
  66. IceCube-221216A - IceCube observation of a high-energy neutrino candidate track-like event
  67. IceCube-221210A - IceCube observation of a high-energy neutrino candidate track-like event
  68. IceCube-221124A - IceCube observation of a high-energy neutrino candidate track-like event
  69. GRB 221120A: Archival PS1 Imaging of Faint Source near XRT position
  70. GRB 221120A: Swift detection of a likely short burst
  71. IceCube-221104A - IceCube observation of a high-energy neutrino candidate track-like event
  72. GRB 221024A: Swift-BAT refined analysis
  73. GRB 221009A: Analysis of the initial episode using data of GBM/Fermi and SPI-ACS/INTEGRAL
  74. GRB 221016A: z-band upper limit, possible afterglow brightening
  75. GRB 221009A: continued Assy optical afterglow observations, possible SN evidence
  76. MAXI GRB 221006A: Redshifts of the possible host galaxies
  77. Afterglow limits of GRB 221006A from OHP
  78. GRB 221009A: Swift detected transient may be GRB
  79. IceCube-220928A - IceCube observation of a high-energy neutrino candidate track-like event
  80. IceCube-220907A: Classification of AT2022oyn as a Type Ia supernova
  81. GRB 220921A: MASTER OT inside Fermi-LAT error-box
  82. Fermi-LAT gamma-ray observations of IceCube-220918A and detection of a new gamma-ray source, Fermi J0502.5+0037
  83. IceCube-220918A - IceCube observation of a high-energy neutrino candidate track-like event
  84. IceCube-220907A - IceCube observation of a high-energy neutrino candidate track-like event
  85. GRB 220831A: DECam detection of a possible optical counterpart
  86. IceCube-220822A: Classification of AT2022saw as a Type Ia supernova
  87. IceCube-220822A: One Candidate Counterpart from the Zwicky Transient Facility
  88. IceCube-220822A - IceCube observation of a high-energy neutrino candidate track-like event
  89. GRB 220813A: VLT optical observations and possible host galaxy
  90. Swift/BAT Trigger 1116172 (=GRB 220714A) is not a real astrophysical event
  91. GRB 220714A: Possible Swift detection of a burst
  92. IceCube-220624A: Classification of AT2022nit as a type Ia supernova and AT2021bei as an AGN
  93. IceCube-220629A - IceCube observation of a high-energy neutrino candidate track-like event
  94. Konus-Wind detection of GRB 220627A
  95. IceCube-220624A: One Candidate Counterpart from Swift/XRT follow up observations
  96. Swift XRT observations of WISEA J145820.77+412101.9 / IceCube 220624A
  97. GRB 220627A: Fermi GBM Detection of a possible Lensed or Ultra-long GRB
  98. IceCube-220627A - IceCube observation of a high-energy neutrino candidate track-like event
  99. GRB 220623A: Swift-BAT refined analysis
  100. IceCube-220624A - IceCube observation of a high-energy neutrino candidate track-like event

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