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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"

30484 results found.

  1. GRB 230812B: continued AbAO optical afterglow observations
  2. GRB 230812B: Optical observaions from Rozhen Observatory
  3. GRB 230812B: Further Bassano Bresciano Observatory optical observations
  4. LIGO/Virgo/KAGRA S230814ah: Identification of a GW compact binary merger candidate
  5. GRB 230812B: further SAO RAS optical observations
  6. GRB 230812B: Upper limits from a neutrino search with IceCube
  7. LIGO/Virgo/KAGRA S230814r: Updated Sky localization
  8. GRB 230812B: GRANDMA further observations of ZTF23aaxeacr candidate afterglow
  9. GRB 230812B: CrAO ZTSh optical observations
  10. GRB 230812B: Koshka Zeiss-1000 optical observations
  11. GRB 230812B: GIT optical follow-up
  12. GRB 230812B: Leavitt Observatory optical observations
  13. GRB 230812B : optical observations from Observatoire de Haute-Provence
  14. GRB 230812B: Bassano Bresciano Observatory optical observations
  15. GRB 230812B: Faulkes Telescope North optical afterglow follow-up
  16. GRB 230812B: Osservatorio Astronomico "Nastro Verde" optical observation
  17. GRB 230812B: rest-frame energetics from Konus-Wind observation
  18. GRB 230812B: OASDG optical observations
  19. GRB 230812B: AbAO optical observations
  20. LIGO/Virgo/KAGRA S230814r: Identification of a GW compact binary merger candidate
  21. GRB 230812B: Spectroscopy from NOT
  22. GRB 230812B: Redshift from OSIRIS+/GTC
  23. GRB 230812B: Montarrenti Observatory optical observations
  24. GRB 230812B: SAO RAS optical observations
  25. GRB 230812B: Detected Optical Afterglow Candidate
  26. GRB 230812B: GMG - GRANDMA observations
  27. Konus-Wind detection of GRB 230812B
  28. GRB 230812B: GECAM-C observation of a very bright burst
  29. GRB 230812: Swift/UVOT Detection
  30. GOTO confirmation and possible host galaxy of GRB230812B optical afterglow
  31. GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
  32. Fermi GRB 230812B: MASTER optical counterpart
  33. GRB 230812B: KAIT Optical Afterglow Candidate
  34. GRB 230812B: Improved Swift/XRT localization
  35. GRB 230812B: Preliminary Swift/XRT localization
  36. GRB 230812B: Fermi-LAT detection
  37. GRB 230812B: Fermi GBM Observation of a very bright burst
  38. Fermi GRB 230812B: Global MASTER-Net observations report
  39. GRB 230812B: Tiled Swift observations
  40. ZTF23aaoohpy/AT2023lcr: JWST spectroscopy confirmation of an associated type Ic-BL supernova
  41. LIGO/Virgo/KAGRA S230811n: Updated Sky localization
  42. GRB 230808A: Fermi GBM Detection
  43. LIGO/Virgo/KAGRA S230811n: Identification of a GW compact binary merger candidate
  44. GRB 230805B: Swift-BAT refined analysis
  45. GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
  46. GRB 230805B: AstroSat CZTI detection
  47. GRB 230808A: Swift/BAT-GUANO detection of a burst
  48. The Fermi GBM Trigger 713134237 / 230807868 is not associated with LIGO/Virgo/KAGRA S230807f.
  49. ZTF23aaoohpy/AT2023lcr: JWST observations consistent with the presence of a supernova
  50. GRB 230805B : MITSuME Akeno optical upper limits
  51. LIGO/Virgo/KAGRA S230808i: Identification of a GW unmodeled transient candidate
  52. LIGO/Virgo/KAGRA S230807f: Updated Sky localization and EM Bright Classification
  53. transient SPT-SVJ025406.5-702837: ATCA follow-up observations
  54. Fermi GRB 230807A: Global MASTER-Net observations report
  55. LIGO/Virgo/KAGRA S230807f: Identification of a GW compact binary merger candidate
  56. Konus-Wind detection of GRB 230803A
  57. GRB 230805B: Fermi GBM observation
  58. GRB 230805B : OHP/T193 optical upper limit
  59. LIGO/Virgo/KAGRA S230806ak: Updated Sky localization and EM Bright Classification
  60. LIGO/Virgo/KAGRA S230806ak: Identification of a GW compact binary merger candidate
  61. GRB 230805B: Swift/UVOT Upper Limits
  62. GRB 230805B: Bassano Bresciano observatory upper limit
  63. GRB 230805B: NOT optical afterglow confirmation
  64. Fermi GRB 230805A: Global MASTER-Net observations report
  65. Swift GRB 230805B: Global MASTER-Net observations report
  66. LIGO/Virgo/KAGRA S230805x: Updated Sky localization
  67. LIGO/Virgo/KAGRA S230805x: Identification of a GW compact binary merger candidate
  68. LIGO/Virgo/KAGRA S230802aq: Updated Sky localization and EM Bright Classification
  69. GRB 230802B: AstroSat CZTI detection
  70. GRB 230802A: Fermi GBM observation
  71. GRB 230802A: Swift-BAT refined analysis
  72. IPN triangulation of GRB 230803A
  73. GRB 230802A: Swift/UVOT Upper Limits
  74. GRB 230803A: AstroSat CZTI detection
  75. Swift GRB 230802A: Global MASTER-Net observations report
  76. LIGO/Virgo/KAGRA S230802aq: Upper limits from Fermi-GBM Observations
  77. LIGO/Virgo S230802aq: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  78. LIGO/Virgo/KAGRA S230802aq: Coverage and upper limits from MAXI/GSC observations
  79. LIGO/Virgo/KAGRA S230802aq: Identification of a GW compact binary merger candidate
  80. IceCube-230724A: JCMT/SCUBA-2 submm observations
  81. IceCube-230707A: JCMT/SCUBA-2 submm observations
  82. GRB 230723A: SPT-3G millimeter-band transient event inconsistent with IPN position
  83. LIGO/Virgo/KAGRA S230731an: Updated Sky Localization and EM Bright Classification, and Correction to Source Classification
  84. LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations
  85. LIGO/Virgo/KAGRA S230731an: Identification of a GW compact binary merger candidate
  86. LIGO/Virgo/KAGRA S230729z: Updated Sky localization
  87. GRB 230728A: Swift-BAT refined analysis
  88. Fermi-LAT gamma-ray observations of IceCube-230727A
  89. GRB 230723B: Swift-BAT refined analysis
  90. GRB 230723B: MITSuME Ishigaki optical observation
  91. IceCube-230727A: No candidates from the Zwicky Transient Facility
  92. LIGO/Virgo/KAGRA S230729z: Identification of a GW compact binary merger candidate
  93. IceCube-230727A: Upper limits from a search for additional neutrino events in IceCube
  94. GRB 230728A: Fermi GBM Observation
  95. GRB 230728A: LCOGT Optical Upper Limit
  96. GRB 230728A: Swift/UVOT Upper Limits
  97. GRB 230728A: NOT optical observations and possible host galaxy
  98. IceCube-230724A: No counterparts from the Zwicky Transient Facility
  99. GRB 230727A: AstroSat CZTI detection
  100. GRB 230727A: Swift/BAT-GUANO detection of a burst

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