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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"

882 results found.

  1. LIGO/Virgo S190910h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  2. LIGO/Virgo S190910d: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  3. LIGO/Virgo S190901ap: No counterpart candidates in INTEGRAL SPI-ACS,prompt observation
  4. LIGO/Virgo S190828l: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  5. LIGO/Virgo S190828j: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  6. Fermi GBM-190816: Location-dependent upper limits from INTEGRAL/SPI-ACS prompt observation
  7. IceCube-190819A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  8. HAWC-190806A: upper limits from INTEGRAL SPI-ACS and IBIS prompt observation
  9. IceCube 190730A: one weakly associated counterpart candidates in INTEGRAL SPI-ACS, and IBIS prompt observation
  10. Fermi-LAT Gamma-ray Observations of IceCube-190712A
  11. Fermi-LAT Gamma-ray Observations of IceCube-190504A
  12. LIGO/Virgo S190426c: Fermi-LAT search for a high-energy gamma-ray counterpart
  13. LIGO/Virgo S190425z: Las Cumbres Observatory Galaxy Targeted Counterpart Search
  14. GRB 190326A: Swift XRT and UVOT follow-up observations
  15. GRB 190326A: Swift-BAT refined analysis - a soft-short GRB or an SGR
  16. INTEGRAL observations of the events in the GWTC-1 catalog
  17. GRB 181201A: a long GRB detected by INTEGRAL
  18. GRB 180828A: Swift detection of a GRB or possible Galactic Transient Swift J1754.9-2548
  19. GRB 180809A: further Swift/XRT observations
  20. GRB 180701A/MAXI J2119-045: CALET Gamma-Ray Burst Monitor data search
  21. GRB 180728A: VLT/X-shooter redshift of a nearby energetic GRB
  22. Fermi GBM triggers 552488966/180705548 and 552490104/180705561 are not GRBs
  23. GRB 180701A: MAXI/GSC detection
  24. Fermi-GBM Detection of possible burst from AXP CXOU J164710.2-455216/PSR J1647-4552
  25. Swift trigger 781740: Further analysis from Swift and Fermi/GBM
  26. Fermi-GBM Detection of possible burst from AXP CXOU J164710.2-455216/PSR J1647-4552
  27. Trigger 780207: Swift triggers again on AXP CXOU J164710.2-455216/PSR J1647-4552
  28. LIGO/Virgo G298048: Chandra X-ray Update on GW170817
  29. LIGO/Virgo G298048: Discovery of X-ray emission from SSS17a in NGC4993
  30. LIGO/Virgo G298936: Astrosat CZTI upper limits
  31. LIGO/Virgo G298048: INTEGRAL pointed follow-up observations
  32. LIGO/Virgo G298048: Chandra X-ray observations
  33. GRB170730A detecetd by INTEGRAL. Refined analysis
  34. Fermi GBM Detection of possible burst from AXP 4U 0142+61
  35. GRB 170524A: Swift detection of a burst (or possible new SGR)
  36. LIGO/Virgo G275697: DLT40 follow-up observation
  37. LIGO/Virgo G268556/GW170104: Lomonosov BDRG observations
  38. GRB 160821B: Swift-BAT refined analysis
  39. GBM observation of SGR-like burst from the direction of PSR 1119-6127
  40. Trigger 706396: Swift detection of a short burst from PSR 1119-6127
  41. GRB 160703, GRB 160705, GRB 160720, SGR1935+2154: First SGRs and GRBs detected by Lomonosov.
  42. SGR 1935+2154: CALET Gamma-Ray Burst Monitor detections
  43. Konus-Wind observation of a bright burst from SGR 1935+2154
  44. SGR 1935+2154: AMI 15 GHz upper limits of the magnetar during outburst
  45. Fermi/GBM observation of a bright burst from magnetar SGR 1935+2154
  46. Swift-BAT refined analysis on the bright event from SGR 1935+2154
  47. Trigger 701590: Swift detection of a bright outburst from SGR 1935+2154
  48. GROND observations of GRB 160622A/SNR RCW 103/SGR 1617-5103
  49. Trigger 701182: Swift detection of SGR 1935+2154
  50. SGR 1617-5103 (BAT trigger 700791): Enhanced Swift-XRT position.
  51. Swift-BAT refined analysis of the recent outburst from SGR 1617-5103 (a.k.a. 1E 161348-5055 and 2E 1613.5-5053)
  52. Fermi GBM Trigger 160622573 is not a GRB
  53. GRB 160622A: Swift detection of a possible short GRB or a new SGR
  54. More FERMI GBM bursts from the magnetar SGR 1935+2154
  55. SGR 1935+2154: MAXI/GSC detection
  56. Fermi GBM trigger 488128598/160620637 is not a GRB
  57. Fermi GBM trigger 487974449/160618852 is not a GRB
  58. Trigger 689353 (possible transient near Sgr A*), Swift-BAT refined analysis
  59. Trigger 689353: Swift detection of a transient near Sgr A*
  60. Fermi GBM trigger 486562774/160602514 is not a GRB
  61. Another Swift detection of SGR 1935+2154 (trigger #687124)
  62. Swift detection of SGR 1935+2154
  63. Konus-Wind observation of a bright burst from SGR 1935+2154
  64. FERMI GBM bursts from the magnetar SGR 1935+2154
  65. SGR 1935+2154: AbAO optical upper limit
  66. Fermi GBM triggers of SGR 1935+2154
  67. Trigger 686761: Swift detection of a bright burst from SGR 1935+2154
  68. Fermi GBM trigger 485124591/160516868 is not a GRB
  69. Trigger 686443: Swift detection of SGR 1935+2154
  70. Fermi GBM trigger 484906918/160514349 is not a GRB
  71. GRB 160401A: a long GRB detected by INTEGRAL
  72. SGR 0755-2933, Swift-BAT refined analysis
  73. Swift detection of a likely new SGR: SGR 0755-2933
  74. IBAS Alert 7313 is SGR J1935+2154
  75. GRB 151221A: INTEGRAL detection of a short burst or possible SGR
  76. Swift-BAT refined analysis of trigger 664624 from SGR J1819-1600
  77. Swift-BAT probable detection of an outburst from SGR J1819-1600 (AX J1818.8-1559)
  78. LIGO/Virgo G184098: Fermi-GBM ground-based follow-up
  79. GRB 150912A: A long GRB detected by INTEGRAL
  80. SGR 1E 1841-045 (Swift trigger 649113): Terskol upper limit
  81. Fermi GBM triggers bn150715759 and bn150715817 are not due to GRBs
  82. Trigger 649113: Swift detection of SGR 1E 1841-045
  83. Swift-XRT observations of GRB 150710A
  84. Swift trigger 642453 is not an astrophysical source
  85. Konus-Wind observation of a bright burst from SGR 1935+2154
  86. IPN Triangulation of a bright burst from SGR 1935+2154
  87. GRB 150301A: Swift-BAT refined analysis
  88. GRB 150301A: Fermi GBM observation
  89. GRB 150301A: Swift detection of a short burst or new SGR
  90. Fermi GBM Observations of SGR 1935+2154
  91. Fermi GBM trigger 150223068 is not a GRB
  92. SGR 1935+2154: Swift-BAT refined analysis
  93. Swift detection of an outburst from SGR 1935+2154
  94. Trigger 607399: Swift detection of SGR1806-20
  95. Fermi GBM Observations of SGR 1935+2154
  96. GRB 140710B: a long GRB detected with INTEGRAL
  97. GRB 140705A / SGR 1935+2154: VLA 6 GHz observations
  98. Pre-discovery observations of SGR 1935+2154 in Swift archival data
  99. GRB 140705A / SGR 1935+2154: Probable association with supernova remnant G57.2+0.8
  100. SGR 1935+2154: Swift-BAT observations of additional short soft events

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