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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"

19551 results found.

  1. GRB 200215A Possible host galaxy in PanSTARRS
  2. GRB 200215A: Nanshan/NEXT optical upper limit
  3. GRB 200215A: Swift detection of a burst
  4. LIGO/Virgo S200213t: MASTER possible Kilonova candidate in PGC315337
  5. LIGO/Virgo S200213t: No neutrino candidates at Pierre Auger Observatory
  6. LIGO/Virgo S200213t: MASTER OT detection in PGC673735
  7. LIGO/Virgo S200213t: No counterpart candidates from Nanshan-0.6m observations
  8. LIGO/Virgo S200213t: No notable candidates in GOTO imaging
  9. LIGO/Virgo S200213t: No candidates found in J-GEM follow-up observations
  10. LIGO/Virgo S200213t: More Candidates from the Zwicky Transient Facility
  11. LIGO/Virgo S200213t: No counterpart candidates in Fermi-LAT observations
  12. LIGO/Virgo S200213t: No Counterparts in DDOTI/OAN Optical Observations
  13. LIGO/Virgo S200213t: MANGROVE catalog galaxy ranking
  14. LIGO/Virgo S191213g: AT2019wxt Wendelstein optical observations
  15. LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
  16. LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
  17. LIGO/Virgo S200213t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  18. LIGO/Virgo S200213t : no neutrino counterpart candidate in ANTARES search
  19. LIGO/Virgo S200213t: Coverage and upper limits from MAXI/GSC observations
  20. GRB 200131A: Tautenburg observations
  21. LIGO/Virgo S200208q: No counterpart candidates in Fermi-LAT observations
  22. LIGO/Virgo S200208q: Coverage and upper limits from MAXI/GSC observations
  23. LIGO/Virgo S200208q: no counterpart candidates in the Swift/BAT observations
  24. LIGO/Virgo S200208q: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  25. LIGO/Virgo S200208q: No counterpart candidates in HAWC observations
  26. LIGO/Virgo S200208q : no neutrino counterpart candidate in ANTARES search
  27. GRB 200208A: Fermi GBM Final Real-time Localization
  28. Swift J0840.7-3516 (AKA GRB 200205A): Swift-BAT refined analysis
  29. Swift Trigger 954840 is not a GRB
  30. GRB 200205B: Swift/UVOT Detection
  31. GRB 200205B: Swift-XRT refined Analysis
  32. GRB 200205A = Swift J0840.7-3516, A newly discovered transient X-ray Pulsar
  33. GRB 200205B: Enhanced Swift-XRT position
  34. GRB 200205A: Enhanced Swift-XRT position
  35. GRB 200205B: Swift detection of a burst with optical counterpart
  36. GRB 200205A: REM optical observations
  37. MAXI GRB200205.29: Global MASTER-Net observations report
  38. GRB 200205A: Swift detection of a burst with a possible UV counterpart
  39. GRB 200131A: Further RATIR Optical Observations
  40. ZTF20aajnksq: Gemini-North r-band photometry
  41. GRB 200131A: ISON-Castelgrande optical observations
  42. GRB 200131A: CDK700 optical observations
  43. GRB 200131A: Swift/UVOT Detection
  44. GRB 200131A: VIRT optical transient detection
  45. GRB 200131A: RATIR Optical Observations
  46. GRB 200131A: Enhanced Swift-XRT position
  47. GRB 200131A: Swift detection of a burst with an optical counterpart
  48. IPN triangulation of GRB 200130B
  49. LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
  50. LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
  51. LIGO/Virgo S200129m: no counterpart candidates in the Swift/BAT observations
  52. LIGO/Virgo S200129m: No counterpart candidates in Fermi-LAT observations
  53. LIGO/Virgo S200128d: No counterpart candidates in Fermi-LAT observations
  54. LIGO/Virgo S200128d: no counterpart candidates in the Swift/BAT observations
  55. Fermi-LAT ANTARES 200127.79 coincidence: MASTER alert observation and presence of young pulsar close to error-box
  56. GRB 200127A: Swift/UVOT Upper Limits
  57. GRB 200127A: Mondy optical upper limit
  58. GRB200127A: Nordic Optical telecope optical upper limit
  59. LIGO/Virgo S200128d : no neutrino counterpart candidate in ANTARES search
  60. GRB 200125B: DDOTI/OAN optical observations report
  61. LIGO/Virgo S200128d: Coverage and upper limits from MAXI/GSC observations
  62. LIGO/Virgo S200128d: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  63. LIGO/Virgo S200128d: No counterpart candidates in HAWC observations
  64. GRB 200127A: Nanshan-0.6m optical upper limit
  65. GRB 200127A: Enhanced Swift-XRT position
  66. GRB 200127A: AbAO optical upper limit
  67. GRB 200127A: Swift detection of a burst
  68. GRB 200125A: Swift/UVOT Upper Limits
  69. GRB 200125A: Further RATIR Optical Observations and Confirmation of Fading
  70. GRB 200125A: AbAO optical upper limit
  71. GRB 200125A: TNG detection of a NIR counterpart candidate
  72. GRB 200125A: Nanshan-0.6m optical upper limit
  73. GRB 200125A: RATIR Optical Observations
  74. GRB 200125A: Enhanced Swift-XRT position
  75. GRB 200125A: Swift detection of a burst
  76. LIGO/Virgo S200114f : No significant candidates in TAROT - FRAM - GRANDMA observations
  77. GRB 200115A: Assy optical observations
  78. GRB 200122A: Mondy optical upper limit
  79. GRB 200122A: RATIR Optical Observations
  80. GRB 200122A: Xinglong-2.16m optical upper limit
  81. GRB 200122A: Swift/UVOT Upper Limits
  82. IPN Triangulation of GRB 200120A
  83. LIGO/Virgo S200115j: Further Swift-XRT sources
  84. GRB 200122A: GOTO non-detection of optical afterglow
  85. GRB 200122A: Swift-XRT refined Analysis
  86. GRB 200122A: Enhanced Swift-XRT position
  87. GRB 200122A: Swift detection of a burst
  88. GRB 191031D: XMM-Newton upper limit
  89. IceCube-200120A: no counterpart candidates in INTEGRAL SPI-ACS and,IBIS prompt observation
  90. IceCube 200117A: No significant detection in HAWC
  91. LIGO/Virgo S200115j: GMOS-N upper limits for ZTF20aafqvyc/AT2020yq from the Gemini Observatory
  92. Fermi-LAT Gamma-ray Observations of IceCube-200117A
  93. LIGO/Virgo S200115j : No significant candidates in TAROT - FRAM - GRANDMA observations
  94. LIGO/Virgo S200115j: Mondy upper limits for ZTF20aafqvyc/AT2020yq
  95. GRB 200115A: Mondy optical observations and correction to GCN 26790
  96. LIGO/Virgo S200115j: NIR upper limits for ZTF20aafqvyc/AT2020yq from the Palomar 200-inch telescope
  97. IceCube-200117A: no counterpart candidates in INTEGRAL SPI-ACS and,IBIS prompt observation
  98. LIGO/Virgo S200114f: No transients found in J-GEM observations of nearby galaxies
  99. GRB 200115A: AROMA-N Optical Observation
  100. LIGO/Virgo S200115j: No notable candidates in GOTO imaging

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