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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"

28041 results found.

  1. LIGO/Virgo S200219ac: upper limits from AGILE/MCAL observations
  2. LIGO/Virgo S200219ac : no neutrino counterpart candidate in ANTARES search
  3. LIGO/Virgo S200219ac: Upper limits from IceCube neutrino searches
  4. LIGO/Virgo S200219ac: No counterpart candidates in HAWC observations
  5. LIGO/Virgo S200219ac: Coverage and upper limits from MAXI/GSC observations
  6. LIGO/Virgo S200219ac: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  7. LIGO/Virgo S200219ac: Identification of a GW compact binary merger candidate
  8. GRB 200216B: second epoch optical upper limit at Mondy observatory
  9. GRB 200219A: MASTER catalog automatic possible Host Galaxy candidate
  10. GRB 200219A: Swift detection of a short burst
  11. GRB 200216B: Mondy and AbAO optical upper limits
  12. LIGO/Virgo (S200213t/IceCube neutrino candidate: No counterpart candidates in the Swift-XRT Observations
  13. GRB 200216B: Swift-XRT refined Analysis
  14. GRB 200216B: Swift-BAT refined analysis
  15. LIGO/Virgo S200213t : No significant candidates in FRAM - OAJ - TAROT - GRANDMA observations
  16. Further Swift-XRT observations of Swift J0840.7-3516
  17. GRB 200216A: Fermi GBM detection
  18. LIGO/Virgo S200213t: AstroSat CZTI upper limits
  19. GRB 200216B: z-band limit from NOT
  20. GRB 200216B: Fermi GBM observation
  21. GRB 200216B: Swift/UVOT Upper Limits
  22. GRB 200216B: Enhanced Swift-XRT position
  23. GRB 200215A: RATIR Optical Observations
  24. GRB 200216B: Nanshan/NEXT early optical upper limit and possible host galaxy
  25. GRB 200216B: GMG upper limit
  26. GRB 200216B: Swift detection of a burst
  27. GRB 200215A: UKIRT H-band observations
  28. GRB 200215A: Swift-BAT refined analysis
  29. LIGO/Virgo S200213t: Updated Sky Localization
  30. LIGO/Virgo S200213t: Updated coverage and candidate list for the Zwicky Transient Facility
  31. LIGO/Virgo S200213t: Updated Sky Localization
  32. GRB 200215A: Swift-XRT refined Analysis
  33. GRB 200215A: Swift/UVOT Upper Limits
  34. GRB 200215A: Enhanced Swift-XRT position
  35. GRB 200215A: Optical observations form Calar Alto 2.2m
  36. GRB 200215A: Fermi GBM detection
  37. GRB 200215A: Liverpool Telescope upper limits
  38. LIGO/Virgo S200213t: Pre-discovery detections of MASTER OT J044008.76-651302.3
  39. GRB 200215A Possible host galaxy in PanSTARRS
  40. GRB 200215A: Nanshan/NEXT optical upper limit
  41. GRB 200215A: Swift detection of a burst
  42. LIGO/Virgo S200213t: MASTER possible Kilonova candidate in PGC315337
  43. LIGO/Virgo S200213t: No neutrino candidates at Pierre Auger Observatory
  44. LIGO/Virgo S200213t: MASTER OT detection in PGC673735
  45. LIGO/Virgo S200213t: Upper limits from Insight-HXMT/HE observations
  46. LIGO/Virgo S200213t: No counterpart candidates from Nanshan-0.6m observations
  47. LIGO/Virgo S200213t: No notable candidates in GOTO imaging
  48. LIGO/Virgo S200213t: No candidates found in J-GEM follow-up observations
  49. LIGO/Virgo S200213t: No counterpart candidates in Fermi-LAT observations
  50. LIGO/Virgo S200213t: No Counterparts in DDOTI/OAN Optical Observations
  51. LIGO/Virgo S200213t: MANGROVE catalog galaxy ranking
  52. LIGO/Virgo S191213g: AT2019wxt Wendelstein optical observations
  53. LIGO/Virgo S200213t: upper limits from AGILE/GRID observations
  54. LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
  55. LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
  56. LIGO/VIRGO S200213t: upper limits from AGILE/MCAL observations
  57. LIGO/Virgo S200213t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  58. LIGO/Virgo S200213t : no neutrino counterpart candidate in ANTARES search
  59. LIGO/Virgo S200213t: Coverage and upper limits from MAXI/GSC observations
  60. LIGO/Virgo S200213t: 1 counterpart neutrino candidate from IceCube neutrino searches
  61. LIGO/Virgo S200213t: Identification of a GW compact binary merger candidate
  62. ZTF20aajnksq: Upper limits from Konus-Wind observations
  63. LIGO/Virgo S200208q: Updated Sky Localization
  64. GRB 200131A: Tautenburg observations
  65. Konus-Wind observation of GRB 200205B
  66. GRB 200211A: BALROG localization (Fermi Trigger 603098793 / GRB 200211310)
  67. LIGO/Virgo S200208q: No counterpart candidates in Fermi-LAT observations
  68. LIGO/Virgo S200129m: Upper limits from Insight-HXMT/HE observations
  69. GRB 200120A: Fermi GBM observation
  70. LIGO/Virgo S200208q: Coverage and upper limits from MAXI/GSC observations
  71. LIGO/Virgo S200208q: no counterpart candidates in the Swift/BAT observations
  72. LIGO/Virgo S200208q: Upper limits from Fermi-GBM Observations
  73. LIGO/Virgo S200208q : upper limits from AGILE/GRID observations
  74. LIGO/Virgo S200208q: upper limits from AGILE/MCAL observations
  75. LIGO/Virgo S200208q: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  76. LIGO/Virgo S200208q: No counterpart candidates in HAWC observations
  77. LIGO/Virgo S200208q : no neutrino counterpart candidate in ANTARES search
  78. LIGO/Virgo S200208q: Upper limits from IceCube neutrino searches
  79. LIGO/Virgo S200208q: Identification of a GW compact binary merger candidate
  80. GRB 200205B: Swift-BAT refined analysis
  81. Swift J0840.7-3516 (AKA GRB 200205A): Swift-BAT refined analysis
  82. Fermi trigger No 602731380: Global MASTER-Net observations report
  83. Swift Trigger 954840 is not a GRB
  84. GRB 200205B: Swift/UVOT Detection
  85. GRB 200205B: Swift-XRT refined Analysis
  86. GRB 200205A = Swift J0840.7-3516, A newly discovered transient X-ray Pulsar
  87. GRB 200205B: Enhanced Swift-XRT position
  88. GRB 200205A: Enhanced Swift-XRT position
  89. GRB 200205B: LCO Optical Detection
  90. GRB 200205B: Swift detection of a burst with optical counterpart
  91. Swift GRB200205.81: Global MASTER-Net OT detection
  92. GRB200120A: SRG/eROSITA discovery of X-ray afterglow
  93. GRB 200205A: REM optical observations
  94. MAXI GRB200205.29: Global MASTER-Net observations report
  95. GRB 200205A: Swift detection of a burst with a possible UV counterpart
  96. LIGO/Virgo S200129m: Upper limits from Konus-Wind observations
  97. LIGO/Virgo S200128d: Upper limits from Konus-Wind observations
  98. GRB 200131A: Further RATIR Optical Observations
  99. AMON IceCube-HAWC_200202A : No neutrino counterpart seen with ANTARES
  100. GRB 200131A: Swift-BAT refined analysis

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