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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"

3139 results found.

  1. GRB 191025B: AstroSat CZTI detection
  2. GRB 191028B: MASTER optical observation
  3. Konus-Wind observation of GRB 191025B
  4. IPN triangulation of GRB 191027A
  5. IPN triangulation of GRB 191025B (short)
  6. GRB 191025B: Insight-HXMT/HE detection
  7. GRB 191026A: Fermi GBM Final Real-time Localization
  8. GRB191024A: MASTER optical observation
  9. GRB 191024A: Swift detection of a burst
  10. Fermi trigger No 593176520: Global MASTER-Net observations report
  11. Fermi trigger No 592818648: Global MASTER-Net observations report
  12. GRB 191011A: correction of reported magnitudes
  13. GRB 191009A: Fermi GBM Final Real-time Localization
  14. Fermi trigger No 592211224: Global MASTER-Net observations report
  15. LIGO/Virgo S190930s: no counterpart candidate in the SVOM/GWAC observations
  16. Swift GRB191004.9: Global MASTER-Net OT detection
  17. LIGO/Virgo S190930t: AT2019rpn, AT2019rpj CrAO continued optical photometry
  18. LIGO/Virgo S190930t: Lulin Follow-up Observations of AT2019rpn and AT2019rpj
  19. LIGO/Virgo S190930s: No counterpart candidates in KAIT observations
  20. LIGO/Virgo S190930t: Transient found in Swift/UVOT counterpart search
  21. Fermi trigger No 591604915: Global MASTER-Net observations report
  22. LIGO/Virgo S190930t: Global MASTER-Net observations report
  23. LIGO/Virgo S190930t: Upper limits from IceCube neutrino searches
  24. Fermi trigger No 591321287: Global MASTER-Net observations report
  25. LIGO/Virgo S190923y: No significant candidates in TAROT-GRANDMA observations
  26. IceCube-190922A: Upper limits from a search for additional neutrino events in IceCube
  27. Fermi-LAT Gamma-ray Observations of IceCube-190922A
  28. IceCube-190922A - HAWC follow-up
  29. IceCube-190922A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  30. IceCube-190922A - IceCube observation of a high-energy neutrino candidate event
  31. LIGO/Virgo S190915ak: No significant candidates in TAROT-GRANDMA observations
  32. LIGO/Virgo S190910h: No significant candidates in TAROT-GRANDMA observations
  33. Fermi trigger No 590335819: Global MASTER-Net observations report
  34. LIGO/Virgo S190915ak: Global MASTER-Net observations report
  35. LIGO/Virgo S190910d : No significant candidates in TAROT-GRANDMA observations
  36. LIGO/Virgo S190814bv: No counterpart candidate after completion of GRAWITA VST-ESO PARANAL transient survey.
  37. LIGO/Virgo S190910d and S190910h: No counterpart candidates in KAIT observations
  38. Update to the Fermi GBM Localizations
  39. LIGO/Virgo S190910d: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  40. LIGO/Virgo S190901ap : No significant candidates found in GRANDMA citizen science observations
  41. LIGO/Virgo S190901ap : No significant candidates in TAROT-GRANDMA
  42. LIGO/Virgo S190901ap: NOT spectroscopy of AT2019pjv
  43. LIGO/Virgo S190901ap: No counterpart candidates in KAIT observations
  44. LIGO/Virgo S190901ap: MASTER OT J171434.95+280725.6/AT2019pjv detection
  45. LIGO/Virgo S190901ap: no counterpart candidate in the SVOM/GWAC observations
  46. GRB 190829A: MeerKAT radio observation
  47. LIGO/Virgo S190901ap Global MASTER-Net observations report
  48. Fermi trigger No 589065714 Global MASTER-Net observations report
  49. LIGO/Virgo S190828j : No significant candidates in TAROT-GRANDMA observations
  50. LIGO/Virgo S190828l: No significant candidates in TAROT-GRANDMA observations
  51. GRB 190830B: Fermi GBM Final Real-time Localization
  52. GRB 190829A: NOT optical afterglow detection and spectroscopy
  53. LIGO/Virgo S190828j: No Counterparts in DDOTI/OAN Optical Observations
  54. LIGO/Virgo S190828l: No counterpart candidates in KAIT observations
  55. LIGO/Virgo S190829u Global MASTER-Net observations report
  56. LIGO/Virgo S190828j: No transient candidates in CALET observations
  57. LIGO/Virgo S190828j: No counterpart candidates in KAIT observations
  58. LIGO/Virgo S190828j: Upper limits from IceCube neutrino searches
  59. GRB 190824A: Fermi GBM Final Real-time Localization
  60. Fermi trigger No 588115134 Global MASTER-Net observations report
  61. Fermi GBM-190816: MASTER-Net optical observation report
  62. LIGO/Virgo S190814bv: No radio counterpart detected in ASKAP observations
  63. LIGO/Virgo S190814bv: No Optical Counterpart Candidates in Second-Epoch Lick/KAIT Observations
  64. Fermi trigger No 588100239 Global MASTER-Net observations report
  65. LIGO/Virgo S190814bv: Further Pan-STARRS observations and transient sources
  66. IceCube-190819A - HAWC follow-up
  67. LIGO/Virgo S190814bv: GRAWITA TNG NIR imaging of AT2019nqq and AT2019nqc
  68. LIGO/Virgo S190814bv: Prioritization of Counterpart Candidates based on a Photometric Redshift Analysis by the DECam-GROWTH Team
  69. LIGO/Virgo S190814bv : No Counterpart Candidates in Continued Galaxy Targeted Search with Magellan
  70. S190814bv: MASTER analysis of DECam-GROWTH candidates
  71. GRB 190816A: Swift detection of a burst
  72. LIGO/Virgo S190814bv : No Counterpart Candidates in Galaxy Targeted Search with Magellan
  73. LIGO/Virgo S190814bv: GRAWITA TNG infrared imaging of selected galaxies
  74. Fermi trigger No 587505927 Global MASTER-Net observations report
  75. LIGO/Virgo S190814bv Global MASTER-Net observations report
  76. LIGO/Virgo S190814bv: No counterpart candidates in KAIT observations
  77. LIGO/Virgo S190814bv: no counterpart candidates in Thacher imaging
  78. LIGO/Virgo S190814bv: no counterpart candidates in Swope imaging
  79. LIGO/Virgo S190814bv: no counterpart candidates in Nickel/Direct imaging and non-detections of 2019nmd and 2019nme
  80. LIGO/Virgo S190814bv: KMTNet observation
  81. LIGO/Virgo S190814bv Global MASTER-Net optical observations
  82. LIGO/Virgo S190814bv: Liverpool Telescope imaging of selected galaxies
  83. LIGO/Virgo S190814bv: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  84. IPN triangulation of GRB 190810A (short)
  85. GRB 190810A: Fermi GBM Final Real-time Localization
  86. GRB 190808B: Fermi GBM Final Real-time Localization
  87. Fermi trigger No 586788607 Global MASTER-Net observations report
  88. GRB 190804B: MAXI/GSC detection
  89. Fermi trigger No 586574612 Global MASTER-Net observations report
  90. GRB 190731A: no OT detected by MASTER
  91. Fermi trigger No 586305505 Global MASTER-Net observations report
  92. LIGO/Virgo S190728q: ZTF Forced Photometry for PS1 and DECam-GROWTH optical candidates, and a note on DECam Photometry from GCN 25215
  93. LIGO/Virgo S190728q: Optical transients from Pan-STARRS coverage during first 2 nights
  94. LIGO/Virgo S190728q: No counterpart candidates in KAIT observations
  95. Fermi trigger No 585988241 Global MASTER-Net observations report
  96. LIGO/Virgo S190727h: No counterpart candidates in KAIT observations
  97. GRB 190727B: Swift detection of a burst
  98. GRB 190720A: CALET Gamma-Ray Burst Monitor detection
  99. IPN triangulation of GRB 190720A
  100. LIGO/Virgo S190720a: No counterpart candidates in KAIT observations

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