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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"

21577 results found.

  1. GRB 231214B: Swift/BAT-GUANO detection of a burst
  2. Fermi trigger No 724278269: Global MASTER-Net observations report
  3. Fermi trigger No 724233240: Global MASTER-Net observations report
  4. Swift GRB231214.85: Global MASTER-Net observations report
  5. GRB 231210B: REM optical/NIR upper limits
  6. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 2047+098, located inside the IceCube-231211A error region
  7. LIGO/Virgo/KAGRA S231206cc: Upper limits from Swift/BAT-GUANO
  8. LIGO/Virgo/KAGRA S231206ca: Upper limits from Swift/BAT-GUANO
  9. Fermi trigger No 724035412: Global MASTER-Net observations report
  10. GRB 231210B: MeerLICHT afterglow observations
  11. IceCube Alert 231211.03: Global MASTER-Net observations report
  12. IceCube-231202A: No candidates from the Zwicky Transient Facility
  13. GRB 231210B: detection of the optical counterpart with the LCOGT 40cm telescope at Sutherland Observatory
  14. Fermi trigger No 723906955: Global MASTER-Net observations report
  15. Swift GRB231210.90: Global MASTER-Net observations report
  16. GRB231205B: Swift/UVOT Upper Limits
  17. GRB 231205B: Swift-BAT refined analysis
  18. GRB 231205B: 1.3m DFOT Optical upper limit
  19. GRB 231205B: optical upper limit in TSHAOand AbAO
  20. Fermi trigger No 723581802: Global MASTER-Net observations report
  21. Fermi-LAT gamma-ray observations of IceCube-231202A
  22. GRB 231205B: REM optical/NIR upper limits
  23. GRB 231205B: NUTTelA-TAO / BSTI Early Optical Limits
  24. GRB 231205B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
  25. GRB 231205B: Zadko observatory - Gingin optical observations
  26. GRB 231205B: Gaoyazi/GOT optical upper limit
  27. GRB 231205B: Nanshan/HMT optical upper limit
  28. Swift GRB231205.70: Global MASTER-Net observations report
  29. Fermi trigger No 723435916: Global MASTER-Net observations report
  30. Fermi trigger No 723326169: Global MASTER-Net observations report
  31. LIGO/Virgo/KAGRA S231129ac: Upper limits from Swift/BAT-GUANO
  32. Fermi trigger No 723412808: Global MASTER-Net observations report
  33. GRB 231203A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  34. Konus-Wind detection of GRB 231129C
  35. Fermi trigger No 723279695: Global MASTER-Net observations report
  36. GRB 231129C: Swift-XRT afterglow detection
  37. Fermi trigger No 723149952: Global MASTER-Net observations report
  38. GRB 231129B: Swift-XRT observations
  39. Optical transient in the field of Messier 31, likely a new blazar: back to bright state
  40. GRB 231129C: Swift/BAT-GUANO localization of a burst outside the coded FOV
  41. GRB 231129A: JinShan optical upper limit
  42. GRB 231129C: Swift-XRT observations
  43. GRB 231129A: Swift/UVOT Upper Limits
  44. GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
  45. GRB 231129C: Tiled Swift observations
  46. Fermi trigger No 722977823: Global MASTER-Net observations report
  47. GRB 231129B: Tiled Swift observations
  48. Fermi-LAT gamma-ray observations of IceCube-231125A
  49. Integral GRB231129.21: Global MASTER-Net observations report
  50. GRB 231117A: MeerKAT 1.3GHz detection
  51. GRB 231123B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  52. Fermi trigger No 722653947: Global MASTER-Net observations report
  53. GRB 231111A: Optical follow-up observations at Terskol, AbAO, Maidanak, Mondy, Assy
  54. Fermi trigger No 722460326: Global MASTER-Net observations report
  55. Fermi trigger No 722507896: Global MASTER-Net observations report
  56. GRB 231123C: Swift/BAT-GUANO detection of a short burst likely outside the coded FOV
  57. Fermi trigger No 722462310: Global MASTER-Net observations report
  58. GRB 231115A: XMM-Newton observation
  59. GRB 231117A: Mondy optical observations
  60. Fermi trigger No 722400249: Global MASTER-Net observations report
  61. GRB 231118A: REM optical afterglow detection
  62. GRB 231122B: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  63. GRB 231117A: Chandra afterglow detection
  64. GRB 231117A: Continued GTC Observations
  65. Fermi trigger No 722349867: Global MASTER-Net observations report
  66. GRB 231118A: ATCA detection of radio counterpart
  67. GRB 231117A: Swift/UVOT late time observations
  68. GRB 231117A: GTC Near-Infrared Observations
  69. LIGO/Virgo/KAGRA S231118d: Upper limits from Swift/BAT-GUANO
  70. LIGO/Virgo/KAGRA S231118an: Upper limits from Swift/BAT-GUANO
  71. LIGO/Virgo/KAGRA S231114n: Upper limits from Swift/BAT-GUANO
  72. LIGO/Virgo/KAGRA S231113bb: Upper limits from Swift/BAT-GUANO
  73. GRB 231117A: AMI-LA radio observations
  74. Konus-Wind detection of GRB 231020A
  75. GRB 231117A: LDT Confirmation of Optical Fading
  76. GRB 231117A: Wendelstein Confirmation of Fading of the Optical Afterglow
  77. 231118A: Swift-UVOT Detection
  78. GRB231117A: Swift-UVOT detection
  79. LIGO/Virgo/KAGRA S231119ab: Coverage and upper limits from MAXI/GSC observations
  80. GRB 231118A: MeerLICHT afterglow detection
  81. GRB 231117A: OHP/T120 optical observations
  82. Fermi trigger No 722039659: Global MASTER-Net observations report
  83. GRB 231117A: Pan-STARRS1 follow-up confirms rapid fading
  84. GRB 231117A: 10 GHz VLA detection
  85. GRB 231118A: LCOGT Optical Observations
  86. GRB 231118A: MASTER OT observation
  87. GRB 231118A: Continued Skynet Observations
  88. Swift GRB231118.72: Global MASTER-Net observations report
  89. GRB 231117A: Kinder observations with Lulin observatory for AT 2023yba without fading in r band
  90. GRB 231117A: Lowell Discovery Telescope Observations
  91. GRB 231117A: ePESSTO+ host galaxy redshift confirmation
  92. GRB 231117A: ATCA detection of a radio counterpart
  93. GRB 231117A: Keck spectroscopy of afterglow candidate
  94. GRB 231115A: Wendelstein Optical/Infrared Observations
  95. GRB 231115A: JinShan optical upper limits
  96. GRB 231117A: LT observations consistent with fading
  97. GRB 231117A: Keck observations indicate presence of optical afterglow in z~0.3-0.5 galaxy
  98. GRB 231117A: REM optical and NIR early-time observations
  99. GRB 231117A: afterglow candidate detection from Kinder observations with Lulin observatory
  100. Swift GRB 231117A: Global MASTER-Net observations report

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