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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"

19549 results found.

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

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