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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"

31730 results found.

  1. GRB 231115A: Wendelstein Optical/Infrared Observations
  2. GRB 231115A: JinShan optical upper limits
  3. LIGO/Virgo/KAGRA S231118d: Identification of a GW compact binary merger candidate
  4. GRB 231117A: GIT optical follow-up
  5. GRB 231117A: LT observations consistent with fading
  6. GRB 231117A: Keck observations indicate presence of optical afterglow in z~0.3-0.5 galaxy
  7. GRB 231117A: REM optical and NIR early-time observations
  8. GRB 231117A: AKO Optical Upper Limit
  9. GRB 231117A: afterglow candidate detection from Kinder observations with Lulin observatory
  10. Swift GRB 231117A: Global MASTER-Net observations report
  11. GRB 231117A (short): Glowbug gamma-ray detection
  12. GRB 231117A: ATLAS non-detection of an optical counterpart
  13. Konus-Wind detection of GRB 231117A (short/hard)
  14. GRB 231115A : OHP/T120 optical upper limit
  15. GRB 231115A: optical observations from INAF observatories
  16. GRB 231117A : MITSuME Akeno optical upper limits
  17. GRB 231117A: AGILE detection of a bright short burst
  18. GRB 231117A: GOTO optical upper limits
  19. GRB 231117A: AstroSat CZTI detection of a bright short burst
  20. GRB 231115A: Non-detection of radio emission with CHIME/FRB
  21. GRB 231111A: Swift/UVOT Detection
  22. MAGIC observation of GRB 231115A, a possible magnetar giant flare
  23. GRB231115A: Liverpool Telescope imaging
  24. GRB 231115A: NuSTAR Follow-Up Observations
  25. GRB 231115A: Swift/BAT-GUANO detection of a short burst
  26. GRB 231115A: Swift-XRT and Swift-UVOT observations
  27. Fermi GRB 231116A: Global MASTER-Net observations report
  28. Konus-Wind detection of GRB 231115A (a probable Magnetar Giant Flare from M82)
  29. GRB 231115A: AGILE/MCAL upper limits
  30. GRB 231115A: Insight-HXMT/HE detection
  31. GRB 231115A: GBM/Fermi Observations of a probable Giant Flare of Magnetar
  32. GRB 231115A : MITSuME Akeno and Okayama optical upper limits
  33. GRB 231115A: Gaoyazi/GOT follow-up and archival observations
  34. GRB 231115A / AT2023xvj: Updated GIT analysis
  35. GRB 231115A: archival Chandra X-ray observations
  36. GRB 231115A: Upper limits from a neutrino search with IceCube
  37. GRB 231115A: Kinder observations with Lulin observatory
  38. GRB231115A: GRANDMA Observations
  39. GRB 231115A: GOTO pre-burst limits of AT2023xvj
  40. GRB 231115A: Non-detection in low-latency of gravitational waves with LIGO/Virgo/KAGRA
  41. GRB 231115A: pre-burst ZTF upper limits for GRB optical counterpart candidate
  42. GRB 231106A: TESS identification of candidate optical counterpart
  43. GRB 231115A: MASTER optical observations
  44. GRB 231115A (short): Glowbug gamma-ray detection
  45. GRB 231115A: Fermi Observations of a probable Magnetar Giant Flare from M82
  46. GRB 231115A: archival HST observations
  47. GRB 231115A: GROWTH-India discovery of a potential optical counterpart
  48. GRB 231115A: Swift ToO observations
  49. Fermi GRB 231115A: Global MASTER-Net observations report
  50. GRB 231115A: significance of INTEGRAL localization alignment with M82
  51. GRB 231115A position consistent with M 82 galaxy
  52. LIGO/Virgo/KAGRA S231113bw: Updated Sky localization, EM Bright Classification, and Source Classification
  53. GRB 231111A: Swift-BAT refined analysis
  54. LIGO/Virgo/KAGRA S231113bw: Zwicky Transient Facility observations
  55. LIGO/Virgo/KAGRA S231114n: Updated Sky localization
  56. Fermi GRB 231114A: Global MASTER-Net observations report
  57. GRB 231114A (short): Glowbug gamma-ray detection
  58. LIGO/Virgo/KAGRA S231113bw: GROWTH-India coverage and upper limits
  59. GECAM-B observation of a short burst from SGR J1555-5402
  60. LIGO/Virgo/KAGRA S231114n: Identification of a GW compact binary merger candidate
  61. LIGO/Virgo/KAGRA S231113bw: Upper limits from Fermi-GBM Observations
  62. GRB 231110A: CALET Gamma-Ray Burst Monitor detection
  63. LIGO/Virgo/KAGRA S231113bb: Updated Sky localization
  64. LIGO/Virgo/KAGRA S231113bw: Coverage and upper limits from MAXI/GSC observations
  65. LIGO/Virgo/KAGRA S231113bw: Identification of a GW compact binary merger candidate
  66. GRB 231110A: Swift-BAT refined analysis
  67. GRB231111A: MDM 2.4m Hiltner Telescope Observation
  68. GRB 231106A: Glowbug gamma-ray detection
  69. GRB 231111A: Xinglong-2.16m optical observations
  70. GRB 231110A: Swift-UVOT Upper Limits
  71. LIGO/Virgo/KAGRA S231113bb: Identification of a GW compact binary merger candidate
  72. GRB 231111A: Afterglow redshift from OSIRIS+/GTC
  73. GRB 231104A: VZLUSAT-2 detection
  74. GRB 231111A: TNG tentative redshift
  75. GRB 231110A: Glowbug gamma-ray detection
  76. GRB 231110A: AstroSat CZTI detection
  77. GRB 231111A NUTTelA-TAO / BSTI Early Measurements
  78. GRB 231111A: Leavitt Observatory optical observations
  79. GRB231111A: Optical follow-up observations with Mephisto
  80. GRB 231111A: GMG observation (correction)
  81. GRB 231111A: GMG observation upper limit
  82. GRB 231111A: Osservatorio Astronomico "Nastro Verde" optical observations with detection of an optical counterpart
  83. GRB 231110A: Terskol Zeiss-2000 optical upper limit
  84. GRB 231111A: Mondy optical observations
  85. GRB 231111A: GECAM-C detection of a long burst (correction)
  86. GRB 231110A: GECAM-B detection (correction)
  87. GRB 231111A: GECAM-C detection of a long burst
  88. GRB 231110A: GECAM detection
  89. GRB 231110A: GOTO optical upper limits
  90. GRB 231110A: SAO RAS optical observations
  91. GRB231111A: YAHPT Observations
  92. GRB231111A: GIT confirmation of the optical afterglow
  93. GRB 231111A: MASTER OT earlier detection
  94. GRB 231111A: Nanshan/HMT optical observations
  95. GRB231110A: WFST Observation and upper limits
  96. LIGO/Virgo/KAGRA S231110g: Updated Sky localization
  97. LIGO/Virgo/KAGRA S231110g: Identification of a GW compact binary merger candidate
  98. IceCube-231103A: No candidates from the Zwicky Transient Facility
  99. LIGO/Virgo/KAGRA S231108u: Updated Sky localization
  100. Fermi GRB 231108A: Global MASTER-Net observations report

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