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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"

30654 results found.

  1. GRB 231118A: MeerLICHT afterglow detection
  2. GRB 231117A: OHP/T120 optical observations
  3. GRB 231118A: VLT/X-shooter redshift
  4. GRB 231117A: Pan-STARRS1 follow-up confirms rapid fading
  5. LIGO/Virgo/KAGRA S231119u: Identification of a GW compact binary merger candidate
  6. GRB 231117A: MAAO 0.7-m telescope optical upper limit
  7. GRB 231117A: AKO Follow-Up Observation
  8. GRB 231117A: GECAM-C detection
  9. GRB 231118A: AstroSat CZTI detection
  10. GRB 231115A: Upper limit from CALET Gamma-Ray Burst Monitor
  11. GRB 231117A: 10 GHz VLA detection
  12. GRB 231118A: Las Cumbres optical detection
  13. GRB 231118A: LCOGT Optical Observations
  14. GRB 231118A: MASTER OT observation
  15. GRB 231118A: Continued Skynet Observations
  16. GRB 231117A: Kinder observations with Lulin observatory for AT 2023yba without fading in r band
  17. GRB 231117A: SOAR/Goodman imaging of the afterglow
  18. GRB 231117A: Lowell Discovery Telescope Observations
  19. GRB 231117A: ePESSTO+ host galaxy redshift confirmation
  20. GRB 231117A: ATCA detection of a radio counterpart
  21. LIGO/Virgo/KAGRA S231118an: Identification of a GW compact binary merger candidate
  22. GRB 231117A: GRBAlpha detection
  23. LIGO/Virgo/KAGRA S231118ab: Identification of a GW compact binary merger candidate
  24. GRB 231117A: Keck spectroscopy of afterglow candidate
  25. GRB 231115A: Wendelstein Optical/Infrared Observations
  26. GRB 231115A: JinShan optical upper limits
  27. LIGO/Virgo/KAGRA S231118d: Identification of a GW compact binary merger candidate
  28. GRB 231117A: GIT optical follow-up
  29. GRB 231117A: LT observations consistent with fading
  30. GRB 231117A: Keck observations indicate presence of optical afterglow in z~0.3-0.5 galaxy
  31. GRB 231117A: REM optical and NIR early-time observations
  32. GRB 231117A: AKO Optical Upper Limit
  33. GRB 231117A: afterglow candidate detection from Kinder observations with Lulin observatory
  34. Swift GRB 231117A: Global MASTER-Net observations report
  35. GRB 231117A (short): Glowbug gamma-ray detection
  36. GRB 231117A: ATLAS non-detection of an optical counterpart
  37. Konus-Wind detection of GRB 231117A (short/hard)
  38. GRB 231115A : OHP/T120 optical upper limit
  39. GRB 231115A: optical observations from INAF observatories
  40. GRB 231117A : MITSuME Akeno optical upper limits
  41. GRB 231117A: AGILE detection of a bright short burst
  42. GRB 231117A: GOTO optical upper limits
  43. GRB 231117A: AstroSat CZTI detection of a bright short burst
  44. GRB 231115A: Non-detection of radio emission with CHIME/FRB
  45. GRB 231111A: Swift/UVOT Detection
  46. MAGIC observation of GRB 231115A, a possible magnetar giant flare
  47. GRB231115A: Liverpool Telescope imaging
  48. GRB 231115A: NuSTAR Follow-Up Observations
  49. GRB 231115A: Swift/BAT-GUANO detection of a short burst
  50. GRB 231115A: Swift-XRT and Swift-UVOT observations
  51. Fermi GRB 231116A: Global MASTER-Net observations report
  52. Konus-Wind detection of GRB 231115A (a probable Magnetar Giant Flare from M82)
  53. GRB 231115A: AGILE/MCAL upper limits
  54. GRB 231115A: Insight-HXMT/HE detection
  55. GRB 231115A: GBM/Fermi Observations of a probable Giant Flare of Magnetar
  56. GRB 231115A : MITSuME Akeno and Okayama optical upper limits
  57. GRB 231115A: Gaoyazi/GOT follow-up and archival observations
  58. GRB 231115A / AT2023xvj: Updated GIT analysis
  59. GRB 231115A: archival Chandra X-ray observations
  60. GRB 231115A: Upper limits from a neutrino search with IceCube
  61. GRB 231115A: Kinder observations with Lulin observatory
  62. GRB231115A: GRANDMA Observations
  63. GRB 231115A: GOTO pre-burst limits of AT2023xvj
  64. GRB 231115A: Non-detection in low-latency of gravitational waves with LIGO/Virgo/KAGRA
  65. GRB 231115A: pre-burst ZTF upper limits for GRB optical counterpart candidate
  66. GRB 231106A: TESS identification of candidate optical counterpart
  67. GRB 231115A: MASTER optical observations
  68. GRB 231115A (short): Glowbug gamma-ray detection
  69. GRB 231115A: Fermi Observations of a probable Magnetar Giant Flare from M82
  70. GRB 231115A: archival HST observations
  71. GRB 231115A: GROWTH-India discovery of a potential optical counterpart
  72. GRB 231115A: Swift ToO observations
  73. Fermi GRB 231115A: Global MASTER-Net observations report
  74. GRB 231115A: significance of INTEGRAL localization alignment with M82
  75. GRB 231115A position consistent with M 82 galaxy
  76. LIGO/Virgo/KAGRA S231113bw: Updated Sky localization, EM Bright Classification, and Source Classification
  77. GRB 231111A: Swift-BAT refined analysis
  78. LIGO/Virgo/KAGRA S231113bw: Zwicky Transient Facility observations
  79. LIGO/Virgo/KAGRA S231114n: Updated Sky localization
  80. Fermi GRB 231114A: Global MASTER-Net observations report
  81. GRB 231114A (short): Glowbug gamma-ray detection
  82. LIGO/Virgo/KAGRA S231113bw: GROWTH-India coverage and upper limits
  83. GECAM-B observation of a short burst from SGR J1555-5402
  84. LIGO/Virgo/KAGRA S231114n: Identification of a GW compact binary merger candidate
  85. LIGO/Virgo/KAGRA S231113bw: Upper limits from Fermi-GBM Observations
  86. GRB 231110A: CALET Gamma-Ray Burst Monitor detection
  87. LIGO/Virgo/KAGRA S231113bb: Updated Sky localization
  88. LIGO/Virgo/KAGRA S231113bw: Coverage and upper limits from MAXI/GSC observations
  89. LIGO/Virgo/KAGRA S231113bw: Identification of a GW compact binary merger candidate
  90. GRB 231110A: Swift-BAT refined analysis
  91. GRB231111A: MDM 2.4m Hiltner Telescope Observation
  92. GRB 231106A: Glowbug gamma-ray detection
  93. GRB 231111A: Xinglong-2.16m optical observations
  94. GRB 231110A: Swift-UVOT Upper Limits
  95. LIGO/Virgo/KAGRA S231113bb: Identification of a GW compact binary merger candidate
  96. GRB 231111A: Afterglow redshift from OSIRIS+/GTC
  97. GRB 231104A: VZLUSAT-2 detection
  98. GRB 231111A: TNG tentative redshift
  99. GRB 231110A: Glowbug gamma-ray detection
  100. GRB 231110A: AstroSat CZTI detection

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