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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').
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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.

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subject:"Swift"
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submitter:"Judith Racusin"

8485 results found.

  1. Fermi-LAT gamma-ray observations of IceCube-230603A
  2. LIGO/Virgo/KAGRA S230605o: Updated Sky localization
  3. IceCube-230603A: Upper limits from a search for additional neutrino events in IceCube
  4. LIGO/Virgo/KAGRA S230601bf: Updated Sky localization
  5. LIGO/Virgo/KAGRA S230605o: Identification of a GW compact binary merger candidate
  6. IceCube-230603A - IceCube observation of a high-energy neutrino candidate track-like event
  7. LIGO/Virgo/KAGRA S230518h: Upper limits from a two-week IceCube neutrino search
  8. LIGO/Virgo/KAGRA S230601bf: Identification of a GW compact binary merger candidate
  9. LIGO/Virgo/KAGRA S230529ay: Upper limits from CALET observations.
  10. LIGO/Virgo/KAGRA S230529ay: Coverage and upper limits from MAXI/GSC observations
  11. LIGO/Virgo/KAGRA S230529ay: Upper limits from Fermi-GBM Observations
  12. LIGO/Virgo/KAGRA S230529ay: Updated Sky localization and EM Bright Classification
  13. LIGO/Virgo/KAGRA S230529ay: Identification of a GW compact binary merger candidate
  14. LIGO/Virgo/KAGRA S230518h: Updated Sky localization
  15. LIGO/Virgo/KAGRA S230520ae: Updated Sky localization
  16. LIGO/Virgo/KAGRA S230518h: Upper limits from Glowbug gamma-ray observations
  17. LIGO/Virgo/KAGRA S230518h: TESS observations of the localization region
  18. IceCube-230524A: Upper limits from a search for additional neutrino events in IceCube
  19. LIGO/Virgo/KAGRA S230524x: Retraction of GW compact binary merger candidate
  20. IceCube-230524A - IceCube observation of a high-energy neutrino candidate track-like event
  21. LIGO/Virgo/KAGRA S230522n: Upper limits from IceCube neutrino search
  22. LIGO/Virgo/KAGRA S230522a: 2 counterpart neutrino candidates from IceCube neutrino searches
  23. LIGO/Virgo/KAGRA S230521k: Zwicky Transient Facility observations
  24. IPN triangulation of GRB 230518A (short)
  25. LIGO/Virgo/KAGRA S230520ae: Identification of a GW compact binary merger candidate: End-to-End Test
  26. LIGO/Virgo/KAGRA S230520ae: Upper limits from IceCube neutrino search
  27. LIGO/Virgo/KAGRA S230518h: ATCA follow-up of candidate counterparts
  28. LIGO/Virgo/KAGRA S230518h: Swope Search and Candidate Counterpart Identification
  29. LIGO/Virgo/KAGRA S230518h: Coverage and upper limits from MAXI/GSC observations
  30. LIGO/Virgo/Kagra S230518h: NED Galaxies in the Localization Volume
  31. LIGO/Virgo/KAGRA S230518h: AstroSat CZTI non-detection and upper limits
  32. LIGO/Virgo/KAGRA S230518h: Upper limits from Fermi-GBM Observations
  33. LIGO/Virgo/KAGRA S230518h: Updated Sky localization and EM Bright Classification
  34. LIGO/Virgo S230518h: Upper limits from IceCube neutrino search
  35. LIGO/Virgo/KAGRA S230518h: Identification of a GW compact binary merger candidate
  36. GRB 230513A: Zwicky Transient Facility continuous observations of a Fermi Short GRB (Trigger 705709044)
  37. IPN triangulation of GRB 230512A
  38. GRB 230513A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  39. GRB 230512A: Nanshan/NEXT non-detection of GRB afterglow candidate
  40. GRB 230512A: Zwicky Transient Facility non-detection of GRB afterglow candidate
  41. GRB 230512A: Liverpool Telescope observations
  42. GRB 230512A: GIT non detection of afterglow candidate
  43. GRB 230512A: Kitab possible afterglow candidate
  44. IceCube-230511A: Upper limits from a search for additional neutrino events in IceCube
  45. IceCube-Cascade 230511A: Upper limits from a search for additional neutrino events in IceCube
  46. GRB 230512A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705565670)
  47. GRB 230430A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 704533643)
  48. GRB 230511D: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705537623)
  49. GRB 230512A: Tiled Swift observations
  50. GRB 230510A: LCOGT Optical Upper Limit
  51. IceCube-230511A: IceCube observation of a high-energy neutrino candidate
  52. GRB 230510A: Swift detection of a burst
  53. IceCube-230506A: Upper limits from a search for additional neutrino events in IceCube
  54. GRB 230506C: Candidate afterglow observation by D50
  55. GRB 230506C: TSHAO possible afterglow candidate
  56. GRB 230506B: Swift/UVOT Detection
  57. IceCube-230506A: IceCube observation of a high-energy neutrino candidate
  58. IceCube-Cascade 230430A: Upper limits from a search for additional neutrino events in IceCube
  59. GRB 230427A: Swift detection of a burst with an optical counterpart
  60. Swift Trigger 1165354 is probably not a GRB
  61. GRB 230420A: Swift detection of a burst
  62. IceCube-Cascade 230417A: Upper limits from a search for additional neutrino events in IceCube
  63. IceCube-230416A: Upper limits from a search for additional neutrino events in IceCube
  64. IceCube-230416A: IceCube observation of a high-energy neutrino candidate
  65. GRB 230414B (correction GRB name in the GCN 33615): Mondy optical afterglow candidate
  66. GRB 230414A: Mondy optical afterglow candidate
  67. GRB 230414B: Swift detection of a burst
  68. IceCube-230405A: BOOTES-4/MET Optical Upper Limits
  69. GRB 230409B: Swift detection of a burst
  70. IceCube-230405A: Upper limits from a search for additional neutrino events in IceCube
  71. GRB 230405B: Swift detection of a burst
  72. GRB 230307A: JWST observations consistent with the presence of a kilonova
  73. IceCube-230405A: IceCube observation of a high-energy neutrino candidate
  74. IceCube-230401A: Upper limits from a search for additional neutrino events in IceCube
  75. IceCube-230401A: IceCube observation of a high-energy neutrino candidate
  76. IceCube-Cascade 230329A: Upper limits from a search for additional neutrino events in IceCube
  77. GRB 230328B: 3.6m DOT multiband optical observation
  78. GRB 230328B: Swift detection of a burst with an optical afterglow
  79. GRB 230322B: Swift-BAT refined analysis
  80. GRB 230325A: Swift detection of a burst
  81. GRB 230322B: Swift detection of a burst with optical counterpart
  82. Trigger 1160641: Swift detection of 4U 1630-472 (a.k.a. SWIFT J1633.8-4724A)
  83. GRB 230307A: INTEGRAL upper limit on Hard X-ray afterglow
  84. GRB 230307A: ATLAS information on the ULTRACAM optical afterglow candidate
  85. GRB 230307A: Erratum of the GCN 33441
  86. GRB 230204B: MASTER detection of an object near NTT Optical Afterglow Candidate
  87. GRB 230307A: optical upper limit
  88. Swift Trigger 1159108 is not a GRB
  89. GRB 230307A: Upper limits from a neutrino search with IceCube
  90. GRB 230307A: Swift-XRT observations
  91. GRB 230307A: Tiled Swift observations
  92. IceCube-230306A: Upper limits from a search for additional neutrino events in IceCube
  93. IceCube-230306A - IceCube observation of a high-energy neutrino candidate
  94. GRB 230228A: Swift detection of a possibly short burst
  95. GRB 230217A: VLT/FORS2 optical observations and candidate counterpart
  96. IceCube-230220A: Upper limits from a search for additional neutrino events in IceCube
  97. IceCube-230217A: Upper limits from a search for additional neutrino events in IceCube
  98. IceCube-230220A - IceCube observation of a high-energy neutrino candidate
  99. IceCube-230217A: BOOTES-4/MET Optical Observations
  100. IceCube-230217A - IceCube observation of a high-energy neutrino candidate track-like event

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