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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"

923 results found.

  1. LIGO/Virgo S190930t: Coverage and upper limits from MAXI/GSC observations
  2. LIGO/Virgo S190930s: Coverage and upper limits from MAXI/GSC observations
  3. LIGO/Virgo S190924h: Coverage and upper limits from MAXI/GSC observations
  4. LIGO/Virgo S190923y: Coverage and upper limits from MAXI/GSC observations
  5. LIGO/Virgo S190915ak: Coverage and upper limits from MAXI/GSC observations
  6. LIGO/Virgo S190910d and S190910h: No counterpart candidates in KAIT observations
  7. LIGO/Virgo S190910h: Coverage and upper limits from MAXI/GSC observations
  8. Swift Trigger 924641 is an outburst from MAXI J1807+132
  9. LIGO/Virgo S190910d: Coverage and upper limits from MAXI/GSC observations
  10. GRB 190823A: Swift-XRT afterglow detection
  11. LIGO/Virgo S190901ap: No counterpart candidates in KAIT observations
  12. LIGO/Virgo S190901ap: Coverage and upper limits from MAXI/GSC observations
  13. LIGO/Virgo S190828l: No counterpart candidates in KAIT observations
  14. GRB 190828A: Swift-XRT observations
  15. LIGO/Virgo S190828j: No counterpart candidates in KAIT observations
  16. GRB 190828A: Tiled Swift observations
  17. LIGO/Virgo S190828l: Coverage and upper limits from MAXI/GSC observations
  18. LIGO/Virgo S190828j: Coverage and upper limits from MAXI/GSC observations
  19. GRB 190828A: MAXI/GSC detection
  20. GRB 190823A: Swift-XRT observations
  21. GRB 190823A: Tiled Swift observations
  22. GRB 190823A: MAXI/GSC detection
  23. Fermi GBM-190816: Coverage and upper limits from MAXI/GSC observations
  24. LIGO/Virgo S190814bv : No Counterpart Candidates in Continued Galaxy Targeted Search with Magellan
  25. LIGO/Virgo S190814bv : No Counterpart Candidates in Galaxy Targeted Search with Magellan
  26. LIGO/Virgo S190814bv: No counterpart candidates in KAIT observations
  27. LIGO/Virgo S190814bv: Coverage and upper limits from MAXI/GSC observations
  28. IPN triangulation of GRB 190805B
  29. LIGO/Virgo S190808ae: Coverage and upper limits from MAXI/GSC observations
  30. GRB 190805B: AstroSat CZTI detection
  31. GRB 190804B: Swift-XRT afterglow detection
  32. Konus-Wind observation of GRB 190805B
  33. GRB 190805B: Swift-XRT observations
  34. GRB 190805B: Fermi GBM detection
  35. GRB 190805B: Tiled Swift observations
  36. GRB 190804B: Swift-XRT observations
  37. GRB 190805B: MAXI/GSC detection
  38. MAXI GRB190804.33 Global MASTER-Net observations report
  39. GRB 190804B: Tiled Swift observations
  40. GRB 190804B: MAXI/GSC detection
  41. LIGO/Virgo S190728q: No counterpart candidates in KAIT observations
  42. LIGO/Virgo S190728q: Coverage and upper limits from MAXI/GSC observations
  43. LIGO/Virgo S190727h: No counterpart candidates in KAIT observations
  44. LIGO/Virgo S190727h: Coverage and upper limits from MAXI/GSC observations
  45. LIGO/Virgo S190720a: No counterpart candidates in KAIT observations
  46. LIGO/Virgo S190720a: Coverage and upper limits from MAXI/GSC observations
  47. LIGO/Virgo S190718y: No counterpart candidates in KAIT observations
  48. LIGO/Virgo S190718y: Coverage and upper limits from MAXI/GSC observations
  49. GRB 190714A: an X-ray flare from 2E 1624.6+1504/UCAC4 525-061488
  50. GRB 190708B: confirmation of the X-ray afterglow
  51. GRB 190714A: Tiled Swift observations
  52. GRB 190714A: MAXI/GSC detection
  53. GRB 190708B: Swift-XRT observations
  54. Konus-Wind observation of GRB 190708B
  55. GRB 190708B: Tiled Swift observations
  56. MAXI GRB190708.83 Global MASTER-Net observations report
  57. GRB 190708B: MAXI/GSC detection
  58. LIGO/Virgo S190706ai: No counterpart candidates in KAIT observations
  59. LIGO/Virgo S190707q: Coverage and upper limits from MAXI/GSC observations
  60. LIGO/Virgo S190706ai: Coverage and upper limits from MAXI/GSC observations
  61. GRB 190706A: MAXI/GSC detection
  62. LIGO/Virgo S190630ag: No counterpart candidates in KAIT observation
  63. LIGO/Virgo S190701ah: Coverage and upper limits from MAXI/GSC observations
  64. GRB 190701A: MAXI/GSC detection
  65. LIGO/Virgo S190630ag: Coverage and upper limits from MAXI/GSC observations
  66. LIGO/Virgo S190602aq: Coverage and upper limits from MAXI/GSC observations
  67. LIGO/Virgo S190521r: Coverage and upper limits from MAXI/GSC observations
  68. IGO/Virgo S190521g: Coverage and upper limits from MAXI/GSC observations
  69. LIGO/Virgo S190519bj: MAXI/GSC Observations
  70. LIGO/Virgo S190517h: MAXI/GSC Observations
  71. LIGO/Virgo S190513bm: Lick/KAIT Follow-Up Observations
  72. LIGO/Virgo S190513bm: MAXI/GSC Observations
  73. LIGO/Virgo S190512at: MAXI/GSC Observations
  74. LIGO/Virgo S190510g: Las Cumbres Observatory Galaxy Targeted Counterpart Search
  75. LIGO/Virgo S190510g: Lick/KAIT Follow-Up Observations
  76. LIGO/Virgo S190510g: Potential host galaxies on the updated skymap from the GLADE catalog
  77. LIGO/Virgo S190510g: MAXI/GSC Observations
  78. LIGO/Virgo S190510g: Potential host galaxies from the GLADE catalog
  79. IceCube-190504A: MASTER optical monitoring analysis
  80. IceCube-190503A: Lick/KAIT Follow-Up Observations
  81. LIGO/Virgo S190503bf: MAXI/GSC Observations
  82. LIGO/Virgo S190426c: YAHPT Optical Observation
  83. LIGO/Virgo S190426c: MMT Follow-Up Observations
  84. LIGO/Virgo S190426c: Lick/KAIT Follow-Up Observations
  85. LIGO/Virgo S190426c: MAXI/GSC Observations
  86. LIGO/Virgo S190425z: Further MMT Follow-Up Observations
  87. LIGO/Virgo S190426c: Potential host galaxies from the GLADE catalog
  88. LIGO/Virgo S190425z: MAXI/GSC Observations
  89. LIGO/Virgo S190425z: Potential host galaxies from the GLADE catalog
  90. LIGO/Virgo S190421ar: MAXI/GSC Observations
  91. Corrections: GRB 190404A (not 140404B ) and GRB 190404B (not 140404C)
  92. LIGO/Virgo S190412m: MAXI/GSC Observations
  93. LIGO/Virgo S190408an: MAXI/GSC Observations
  94. GRB 190404C: MITSuME Akeno and Okayama optical upper limits
  95. Konus-Wind observation of GRB 190404B
  96. CORRECTED TARGET NAME: GRB 190408A: MAXI/GSC detection
  97. GRB 140408A: MAXI/GSC detection
  98. GRB 190404C: Swift-XRT afterglow detection
  99. GRB 190404B: CALET Gamma-Ray Burst Monitor detection
  100. GRB 190404C: Swift-XRT observations

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