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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"

32544 results found.

  1. LIGO/Virgo/KAGRA S230811n: Updated Sky localization
  2. GRB 230808A: Fermi GBM Detection
  3. LIGO/Virgo/KAGRA S230811n: Identification of a GW compact binary merger candidate
  4. GRB 230805B: Swift-BAT refined analysis
  5. GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
  6. GRB 230805B: AstroSat CZTI detection
  7. GRB 230808A: Swift/BAT-GUANO detection of a burst
  8. The Fermi GBM Trigger 713134237 / 230807868 is not associated with LIGO/Virgo/KAGRA S230807f.
  9. ZTF23aaoohpy/AT2023lcr: JWST observations consistent with the presence of a supernova
  10. GRB 230805B : MITSuME Akeno optical upper limits
  11. LIGO/Virgo/KAGRA S230808i: Identification of a GW unmodeled transient candidate
  12. LIGO/Virgo/KAGRA S230807f: Updated Sky localization and EM Bright Classification
  13. transient SPT-SVJ025406.5-702837: ATCA follow-up observations
  14. Fermi GRB 230807A: Global MASTER-Net observations report
  15. LIGO/Virgo/KAGRA S230807f: Identification of a GW compact binary merger candidate
  16. Konus-Wind detection of GRB 230803A
  17. GRB 230805B: Fermi GBM observation
  18. GRB 230805B : OHP/T193 optical upper limit
  19. LIGO/Virgo/KAGRA S230806ak: Updated Sky localization and EM Bright Classification
  20. LIGO/Virgo/KAGRA S230806ak: Identification of a GW compact binary merger candidate
  21. GRB 230805B: Swift/UVOT Upper Limits
  22. GRB 230805B: Bassano Bresciano observatory upper limit
  23. GRB 230805B: NOT optical afterglow confirmation
  24. Fermi GRB 230805A: Global MASTER-Net observations report
  25. Swift GRB 230805B: Global MASTER-Net observations report
  26. LIGO/Virgo/KAGRA S230805x: Updated Sky localization
  27. LIGO/Virgo/KAGRA S230805x: Identification of a GW compact binary merger candidate
  28. LIGO/Virgo/KAGRA S230802aq: Updated Sky localization and EM Bright Classification
  29. GRB 230802B: AstroSat CZTI detection
  30. GRB 230802A: Fermi GBM observation
  31. GRB 230802A: Swift-BAT refined analysis
  32. IPN triangulation of GRB 230803A
  33. GRB 230802A: Swift/UVOT Upper Limits
  34. GRB 230803A: AstroSat CZTI detection
  35. Swift GRB 230802A: Global MASTER-Net observations report
  36. LIGO/Virgo/KAGRA S230802aq: Upper limits from Fermi-GBM Observations
  37. LIGO/Virgo S230802aq: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  38. LIGO/Virgo/KAGRA S230802aq: Coverage and upper limits from MAXI/GSC observations
  39. LIGO/Virgo/KAGRA S230802aq: Identification of a GW compact binary merger candidate
  40. IceCube-230724A: JCMT/SCUBA-2 submm observations
  41. IceCube-230707A: JCMT/SCUBA-2 submm observations
  42. GRB 230723A: SPT-3G millimeter-band transient event inconsistent with IPN position
  43. LIGO/Virgo/KAGRA S230731an: Updated Sky Localization and EM Bright Classification, and Correction to Source Classification
  44. LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations
  45. LIGO/Virgo/KAGRA S230731an: Identification of a GW compact binary merger candidate
  46. LIGO/Virgo/KAGRA S230729z: Updated Sky localization
  47. GRB 230728A: Swift-BAT refined analysis
  48. Fermi-LAT gamma-ray observations of IceCube-230727A
  49. GRB 230723B: Swift-BAT refined analysis
  50. GRB 230723B: MITSuME Ishigaki optical observation
  51. IceCube-230727A: No candidates from the Zwicky Transient Facility
  52. LIGO/Virgo/KAGRA S230729z: Identification of a GW compact binary merger candidate
  53. IceCube-230727A: Upper limits from a search for additional neutrino events in IceCube
  54. GRB 230728A: Fermi GBM Observation
  55. GRB 230728A: LCOGT Optical Upper Limit
  56. GRB 230728A: Swift/UVOT Upper Limits
  57. GRB 230728A: NOT optical observations and possible host galaxy
  58. IceCube-230724A: No counterparts from the Zwicky Transient Facility
  59. GRB 230727A: AstroSat CZTI detection
  60. GRB 230727A: Swift/BAT-GUANO detection of a burst
  61. Fermi-LAT gamma-ray observations of IceCube-230725A
  62. Fermi-LAT gamma-ray observations of IceCube-230724A
  63. IceCube-230725A: Upper limits from a search for additional neutrino events in IceCube
  64. IceCube-230724A: Upper limits from a search for additional neutrino events in IceCube
  65. GRB 230723B: Further CAHA observations and host galaxy detection
  66. LIGO/Virgo/KAGRA S230726a: Updated Sky localization
  67. Konus-Wind detection of GRB 230723A
  68. GRB 230723B: MITSuME Akeno optical afterglow candidate detection
  69. GRB 230723B: ATCA rapid radio follow-up
  70. LIGO/Virgo/KAGRA S230726a: Identification of a GW compact binary merger candidate
  71. GRB 230723B: GAD Observatory, La Spezia, Italy upper limit
  72. IPN triangulation of GRB 230723A (short)
  73. GRB 230723B: Osservatorio Astronomico Nastro Verde upper limit
  74. GRB 230723B: Montarrenti Observatory upper limit
  75. GRB 230723B: Optical afterglow candidate from CAHA
  76. GRB 230723B: Bassano Bresciano Observatory upper limit
  77. GRB 230723B: Fermi GBM observation
  78. GRB 230723B: non-detections from Observatoire de Haute-Provence
  79. LIGO/Virgo/KAGRA S230723ac: Updated Sky localization
  80. GRB 230723B: Optical limit from CAHA
  81. GRB 230723B: Swift/UVOT Upper Limits
  82. Swift GRB 230723B: Global MASTER-Net observations report
  83. LIGO/Virgo/KAGRA S230723ac: Identification of a GW compact binary merger candidate
  84. Fermi GRB 230723A: Global MASTER-Net observations report
  85. Swift Trigger 1180060 is not a GRB
  86. GRB 230718A: Final Localization Correction
  87. IPN triangulation of GRB 230712A (short)
  88. LIGO/Virgo/KAGRA S230708z: Updated Sky localization
  89. Fermi GRB 230713A: Global MASTER-Net observations report
  90. IceCube-230707A : MAXI upper limit and NICER follow-up observation of Swift J1753.5-0127
  91. LIGO/Virgo/KAGRA S230709bi: Updated Sky localization
  92. LIGO/Virgo/KAGRA S230708t: Updated Sky localization
  93. GRB 230709B: CALET Gamma-Ray Burst Monitor detection
  94. GRB 230703A: CALET Gamma-Ray Burst Monitor detection
  95. GRB 230709C: Swift/BAT-GUANO detection of a short burst outside the coded FOV
  96. IceCube-230708A: Upper limits from Swift/BAT-GUANO
  97. GRB 230707A: Swift/BAT-GUANO position correction
  98. IceCube-230708A - Correction to GCN Circular 34170
  99. GRB 230709C: GRBAlpha detection
  100. GRB 230709B: GRBAlpha detection

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