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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"

2707 results found.

  1. LXT 240402A/GRB 240402B: Swift follow-up observations
  2. EP240414a: Kinder optical counterpart candidate possibly associated with the galaxy SDSS J124601.99-094309.3
  3. EP240413a: possible detection of the X-ray emission with EP-FXT after 14 hours
  4. GRB 240414A: Swift detection of a burst
  5. IceCube-240412A - IceCube observation of a high-energy neutrino candidate track-like event
  6. EP240408a: Swift follow-up observation
  7. X-ray transient EP240331a: Kinder optical upper limits
  8. IceCube-240327B - IceCube observation of a high-energy neutrino candidate track-like event
  9. IceCube-240327A - IceCube observation of a high-energy neutrino candidate track-like event
  10. X-ray transient EP240315a: e-MERLIN radio observations
  11. Transient EPW20240219aa: REM optical/NIR further observations
  12. Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
  13. GRB 240315C / X-ray transient EP240315a: Swift/BAT detection
  14. Swift satellite in safe mode
  15. X-ray transient EP240315a: Montarrenti Observatory optical upper limit
  16. X-ray transient EP240315a: orphan FXT?
  17. X-ray transient EP240315a: Kinder follow-up observations for AT 2024eju with Lulin observatory
  18. AT2024eju: followup observations with Liverpool Telescope suggest a fading transient
  19. X-ray transient EP240315a: ATLAS detection of a possible optical counterpart AT2024eju
  20. IceCube-240307A - IceCube observation of a high-energy neutrino candidate track-like event
  21. IceCube-240229A - IceCube observation of a high-energy neutrino candidate track-like event
  22. Transient EPW20240219aa: upper limit in gamma-ray range from SPI-ACS/INTEGRAL observations
  23. Transient EPW20240219aa: Liverpool Telescope non-detection and limiting magnitude
  24. Fermi GBM Sub-Threshold Detection of EPW20240219aa as a likely GRB
  25. GRB 240209A: Classification of AT2024cew/GOTO24pw as Type Ia-pec supernova
  26. GRB 240214A/1H 0451-560: MAXI/GSC detection
  27. IceCube-240204A - IceCube observation of a high-energy neutrino candidate track-like event
  28. IceCube-240123A - IceCube observation of a high-energy neutrino candidate track-like event
  29. GRB 240123A: Swift detection of a burst with a possible optical counterpart
  30. IceCube-240105A: Detection of NIR flare of PKS 0446+11 with WINTER
  31. IceCube-240105A - IceCube observation of a high-energy neutrino candidate track-like event
  32. GRB 240101B: Swift-BAT refined analysis
  33. IceCube-231211A - IceCube observation of a high-energy neutrino candidate track-like event
  34. IceCube-231202A - IceCube observation of a high-energy neutrino candidate track-like event
  35. IceCube-231125A - IceCube observation of a high-energy neutrino candidate track-like event
  36. GRB 231117A: Keck spectroscopy of afterglow candidate
  37. MAGIC observation of GRB 231115A, a possible magnetar giant flare
  38. GRB231115A: Liverpool Telescope imaging
  39. GRB 231115A: AGILE/MCAL upper limits
  40. GRB 231115A: significance of INTEGRAL localization alignment with M82
  41. GRB 231111A: TNG tentative redshift
  42. GRB231110A: WFST Observation and upper limits
  43. IceCube-231103A - IceCube observation of a high-energy neutrino candidate track-like event
  44. IceCube-231027A - IceCube observation of a high-energy neutrino candidate track-like event
  45. IC231004A: GRANDMA observations of AT2023uqf/ZTF23abidzvf candidate
  46. GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
  47. GRB 230911C: ATCA detection of possible radio counterpart
  48. IC231004A: Classification of AT2023uqf/ZTF23abidzvf as a rapidly-evolving supernova with CSM interaction
  49. IceCube-231014A - IceCube observation of a high-energy neutrino candidate track-like event
  50. IceCube-231004A - IceCube observation of a high-energy neutrino candidate track-like event
  51. transient AT2023sva: A Binary Driven Hypernova with a possible associated supernova
  52. LIGO/Virgo/KAGRA S230904n: Classification of the candidate AT2023rkw with DBSP
  53. Correction to Fermi GBM Statement for Trigger 716527670/230916144
  54. LIGO/Virgo S230917af: Swift XRT observations, 6 X-ray sources
  55. IceCube-230914A - IceCube observation of a high-energy neutrino candidate track-like event
  56. GRB 230911D: NuSTAR Detection of Prompt Emission
  57. IceCube-230823A - IceCube observation of a high-energy neutrino candidate track-like event
  58. GRB 230812B: Assy optical observations, possible SN rise
  59. GRB 230812B: SAO RAS observations, possible re-brightening
  60. GRB 230812B: SAO RAS optical observations
  61. GRB230816A: Possible host and GIT detection of optical counterpart
  62. GOTO confirmation and possible host galaxy of GRB230812B optical afterglow
  63. GRB 230805B: SAO RAS optical observations
  64. GRB 230728A: NOT optical observations and possible host galaxy
  65. IceCube-230727A - IceCube observation of a high-energy neutrino candidate track-like event
  66. IceCube-230724A - IceCube observation of a high-energy neutrino candidate track-like event
  67. IceCube-230725A - IceCube observation of a high-energy neutrino candidate track-like event
  68. GRB 230723B: Optical afterglow candidate from CAHA
  69. GRB 230723B: Optical limit from CAHA
  70. Swift Trigger 1178410: possible GRB 230709A
  71. IceCube-230708A - IceCube observation of a high-energy neutrino candidate track-like event
  72. IceCube-230707B - IceCube observation of a high-energy neutrino candidate track-like event
  73. IceCube-230707A - IceCube observation of a high-energy neutrino candidate track-like event
  74. GRB 230628E - VLT spectroscopic observations
  75. LIGO/Virgo/KAGRA S230627c: ATLAS information on the ZTF candidates
  76. Fermi GBM-230619: A soft subthreshold candidate potentially associated with a subthreshold LIGO/Virgo compact binary merger candidate
  77. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Swift/UVOT detection
  78. AT2023lcr: Pan-STARRS & ATLAS Observations
  79. ZTF23aaoohpy/AT2023lcr: Keck/LRIS spectroscopy and redshift
  80. LIGO/Virgo/KAGRA S230615az: GOTO candidate counterparts
  81. IceCube-230603A - IceCube observation of a high-energy neutrino candidate track-like event
  82. IceCube-230524A - IceCube observation of a high-energy neutrino candidate track-like event
  83. LIGO/Virgo/KAGRA S230518h: ATLAS observations of the skymap
  84. GRB 230512A: Kitab possible afterglow candidate
  85. IceCube-230511A: IceCube observation of a high-energy neutrino candidate
  86. GRB 230506C: TSHAO possible afterglow candidate
  87. IceCube-230506A: IceCube observation of a high-energy neutrino candidate
  88. GRB 230430A: A short GRB from a neutron star merger
  89. GRB 230420A: Lowell Discovery Telescope Optical Detection
  90. GRB 230420A: Swift-BAT refined analysis
  91. IceCube-230416A: IceCube observation of a high-energy neutrino candidate
  92. GRB 230414B (correction GRB name in the GCN 33615): Mondy optical afterglow candidate
  93. GRB 230328B: redshift lower limit estimating
  94. GRB 230307A: JWST NIRSpec observations, possible higher redshift
  95. GRB 230307A: short mininum variability timescale compatible with a merger origin
  96. IceCube-230405A: IceCube observation of a high-energy neutrino candidate
  97. Fermi-LAT gamma-ray observations of IceCube-230401A and detection of Fermi J0030.2+0005
  98. IceCube-230401A: IceCube observation of a high-energy neutrino candidate
  99. GRB 230307A: INTEGRAL upper limit on Hard X-ray afterglow
  100. GRB 230307A: SOAR/Goodman detection of the possible host galaxy

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