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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"

32540 results found.

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

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