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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"

7301 results found.

  1. LIGO/Virgo/KAGRA S230518h: Updated Sky localization
  2. LIGO/Virgo/KAGRA S230520ae: Updated Sky localization
  3. LIGO/Virgo/KAGRA S230518h: Upper limits from Glowbug gamma-ray observations
  4. LIGO/Virgo/KAGRA S230518h: TESS observations of the localization region
  5. LIGO/Virgo/KAGRA S230524x: Retraction of GW compact binary merger candidate
  6. IceCube-230524A - IceCube observation of a high-energy neutrino candidate track-like event
  7. LIGO/Virgo/KAGRA S230522n: Upper limits from IceCube neutrino search
  8. LIGO/Virgo/KAGRA S230522a: 2 counterpart neutrino candidates from IceCube neutrino searches
  9. LIGO/Virgo/KAGRA S230521k: Zwicky Transient Facility observations
  10. IPN triangulation of GRB 230518A (short)
  11. LIGO/Virgo/KAGRA S230520ae: Identification of a GW compact binary merger candidate: End-to-End Test
  12. LIGO/Virgo/KAGRA S230520ae: Upper limits from IceCube neutrino search
  13. LIGO/Virgo/KAGRA S230518h: ATCA follow-up of candidate counterparts
  14. LIGO/Virgo/KAGRA S230518h: ATLAS observations of the skymap
  15. LIGO/Virgo/KAGRA S230518h: Swope Search and Candidate Counterpart Identification
  16. LIGO/Virgo/KAGRA S230518h: Coverage and upper limits from MAXI/GSC observations
  17. LIGO/Virgo/Kagra S230518h: NED Galaxies in the Localization Volume
  18. LIGO/Virgo/KAGRA S230518h: AstroSat CZTI non-detection and upper limits
  19. LIGO/Virgo/KAGRA S230518h: Upper limits from Fermi-GBM Observations
  20. LIGO/Virgo/KAGRA S230518h: Updated Sky localization and EM Bright Classification
  21. LIGO/Virgo S230518h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  22. LIGO/Virgo S230518h: Upper limits from IceCube neutrino search
  23. LIGO/Virgo/KAGRA S230518h: Identification of a GW compact binary merger candidate
  24. GRB 230513A: Zwicky Transient Facility continuous observations of a Fermi Short GRB (Trigger 705709044)
  25. IPN triangulation of GRB 230512A
  26. GRB 230513A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  27. GRB 230512A: Nanshan/NEXT non-detection of GRB afterglow candidate
  28. GRB 230512A: Zwicky Transient Facility non-detection of GRB afterglow candidate
  29. GRB 230512A: Liverpool Telescope observations
  30. GRB 230512A: GIT non detection of afterglow candidate
  31. GRB 230512A: Kitab possible afterglow candidate
  32. GRB 230512A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705565670)
  33. GRB 230430A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 704533643)
  34. GRB 230511D: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705537623)
  35. GRB 230512A: Tiled Swift observations
  36. GRB 230510A: LCOGT Optical Upper Limit
  37. IceCube-230511A: IceCube observation of a high-energy neutrino candidate
  38. GRB 230510A: Swift detection of a burst
  39. GRB 230506C: Candidate afterglow observation by D50
  40. GRB 230506C: TSHAO possible afterglow candidate
  41. GRB 230506B: Swift/UVOT Detection
  42. IceCube-230506A: IceCube observation of a high-energy neutrino candidate
  43. GRB 230430A: A short GRB from a neutron star merger
  44. GRB 230427A: Swift detection of a burst with an optical counterpart
  45. Swift Trigger 1165354 is probably not a GRB
  46. GRB 230420A: Swift detection of a burst
  47. IceCube-230416A: IceCube observation of a high-energy neutrino candidate
  48. GRB 230414B (correction GRB name in the GCN 33615): Mondy optical afterglow candidate
  49. GRB 230414A: Mondy optical afterglow candidate
  50. GRB 230414B: Swift detection of a burst
  51. GRB 230409B: Swift detection of a burst
  52. GRB 230307A: JWST NIRSpec observations, possible higher redshift
  53. GRB 230307A: further analysis of the Konus-Wind detection and rest-frame energetics
  54. GRB 230307A: good match with kilonova models
  55. GRB 230307A: short mininum variability timescale compatible with a merger origin
  56. GRB 230405B: Swift detection of a burst
  57. GRB 230307A: JWST observations consistent with the presence of a kilonova
  58. IceCube-230405A: IceCube observation of a high-energy neutrino candidate
  59. IceCube-230401A: IceCube observation of a high-energy neutrino candidate
  60. GRB 230328B: Swift detection of a burst with an optical afterglow
  61. GRB 230325A: Swift detection of a burst
  62. GRB 230322B: Swift detection of a burst with optical counterpart
  63. GRB 230314A: TURBO Optical Upper Limit
  64. Trigger 1160641: Swift detection of 4U 1630-472 (a.k.a. SWIFT J1633.8-4724A)
  65. GRB 230307A: INTEGRAL upper limit on Hard X-ray afterglow
  66. GRB 230307A: ATLAS information on the ULTRACAM optical afterglow candidate
  67. GRB 230307A: Erratum of the GCN 33441
  68. GRB 230204B: MASTER detection of an object near NTT Optical Afterglow Candidate
  69. GRB 230307A: optical upper limit
  70. Swift Trigger 1159108 is not a GRB
  71. GRB 230307A: Swift-XRT observations
  72. GRB 230307A: Tiled Swift observations
  73. IceCube-230306A - IceCube observation of a high-energy neutrino candidate
  74. GRB 230228A: Swift detection of a possibly short burst
  75. GRB 230217A: VLT/FORS2 optical observations and candidate counterpart
  76. IceCube-230220A - IceCube observation of a high-energy neutrino candidate
  77. IceCube-230217A: BOOTES-4/MET Optical Observations
  78. IceCube-230217A - IceCube observation of a high-energy neutrino candidate track-like event
  79. GRB 230205A: Lowell Discovery Telescope Observations
  80. GRB 230216A: Swift detection of a burst
  81. Outburst from LS V +44 17 / RX J0440.9+4431: Transient detection by GRBAlpha
  82. Swift Trigger 1153670 is probably not a GRB
  83. GRB 230205A: SUBARU HSC pre-imaging for host galaxy search
  84. GRB 230205A: possible host galaxy detection with the Schmidt - Asiago telescope
  85. GRB 230204B: Swift ToO observations
  86. GRB 230205A: Swift detection of a burst
  87. GRB 230204B: GIT discovery of the likely optical afterglow
  88. GRB 230204A/Swift J1552.8-5055: LCOGT Optical Counterpart Candidate
  89. GRB 230204A: Swift detection of a possible burst (or possible transient Swift J1552.8-5055)
  90. GRB 230201B: TURBO Optical Upper Limits
  91. ZTF23aaarlti/AT2023avj: AMI-LA radio detection
  92. ZTF23aabmzlp/AT2023azs: AMI-LA radio upper limit
  93. IceCube-230201A - IceCube observation of a high-energy neutrino candidate track-like event
  94. ZTF23aabmzlp/AT2023azs: LCOGT Optical Detection
  95. ZTF23aabmzlp/AT2023azs: 1.3m DFOT optical observations
  96. ZTF23aabmzlp/AT2023azs: GIT confirmation of the likely afterglow
  97. AT2023avj ZTF Candidate: Assy optical observations
  98. ZTF and LT Observations of AT2023avj, a Candidate Optical Afterglow
  99. GRB 230123A: Swift detection of a burst
  100. IceCube-230122A - IceCube observation of a high-energy neutrino candidate track-like event

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