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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"

877 results found.

  1. Fermi GBM-190816: Location-dependent upper limits from INTEGRAL/SPI-ACS prompt observation
  2. IceCube-190819A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  3. HAWC-190806A: upper limits from INTEGRAL SPI-ACS and IBIS prompt observation
  4. IceCube 190730A: one weakly associated counterpart candidates in INTEGRAL SPI-ACS, and IBIS prompt observation
  5. Fermi-LAT Gamma-ray Observations of IceCube-190712A
  6. Fermi-LAT Gamma-ray Observations of IceCube-190504A
  7. LIGO/Virgo S190426c: Fermi-LAT search for a high-energy gamma-ray counterpart
  8. LIGO/Virgo S190425z: Las Cumbres Observatory Galaxy Targeted Counterpart Search
  9. GRB 190326A: Swift XRT and UVOT follow-up observations
  10. GRB 190326A: Swift-BAT refined analysis - a soft-short GRB or an SGR
  11. INTEGRAL observations of the events in the GWTC-1 catalog
  12. GRB 181201A: a long GRB detected by INTEGRAL
  13. GRB 180828A: Swift detection of a GRB or possible Galactic Transient Swift J1754.9-2548
  14. GRB 180809A: further Swift/XRT observations
  15. GRB 180701A/MAXI J2119-045: CALET Gamma-Ray Burst Monitor data search
  16. GRB 180728A: VLT/X-shooter redshift of a nearby energetic GRB
  17. Fermi GBM triggers 552488966/180705548 and 552490104/180705561 are not GRBs
  18. GRB 180701A: MAXI/GSC detection
  19. Fermi-GBM Detection of possible burst from AXP CXOU J164710.2-455216/PSR J1647-4552
  20. Swift trigger 781740: Further analysis from Swift and Fermi/GBM
  21. Fermi-GBM Detection of possible burst from AXP CXOU J164710.2-455216/PSR J1647-4552
  22. Trigger 780207: Swift triggers again on AXP CXOU J164710.2-455216/PSR J1647-4552
  23. LIGO/Virgo G298048: Chandra X-ray Update on GW170817
  24. LIGO/Virgo G298048: Discovery of X-ray emission from SSS17a in NGC4993
  25. LIGO/Virgo G298936: Astrosat CZTI upper limits
  26. LIGO/Virgo G298048: INTEGRAL pointed follow-up observations
  27. LIGO/Virgo G298048: Chandra X-ray observations
  28. GRB170730A detecetd by INTEGRAL. Refined analysis
  29. Fermi GBM Detection of possible burst from AXP 4U 0142+61
  30. GRB 170524A: Swift detection of a burst (or possible new SGR)
  31. LIGO/Virgo G275697: DLT40 follow-up observation
  32. LIGO/Virgo G268556/GW170104: Lomonosov BDRG observations
  33. GRB 160821B: Swift-BAT refined analysis
  34. GBM observation of SGR-like burst from the direction of PSR 1119-6127
  35. Trigger 706396: Swift detection of a short burst from PSR 1119-6127
  36. GRB 160703, GRB 160705, GRB 160720, SGR1935+2154: First SGRs and GRBs detected by Lomonosov.
  37. SGR 1935+2154: CALET Gamma-Ray Burst Monitor detections
  38. Konus-Wind observation of a bright burst from SGR 1935+2154
  39. SGR 1935+2154: AMI 15 GHz upper limits of the magnetar during outburst
  40. Fermi/GBM observation of a bright burst from magnetar SGR 1935+2154
  41. Swift-BAT refined analysis on the bright event from SGR 1935+2154
  42. Trigger 701590: Swift detection of a bright outburst from SGR 1935+2154
  43. GROND observations of GRB 160622A/SNR RCW 103/SGR 1617-5103
  44. Trigger 701182: Swift detection of SGR 1935+2154
  45. SGR 1617-5103 (BAT trigger 700791): Enhanced Swift-XRT position.
  46. Swift-BAT refined analysis of the recent outburst from SGR 1617-5103 (a.k.a. 1E 161348-5055 and 2E 1613.5-5053)
  47. Fermi GBM Trigger 160622573 is not a GRB
  48. GRB 160622A: Swift detection of a possible short GRB or a new SGR
  49. More FERMI GBM bursts from the magnetar SGR 1935+2154
  50. SGR 1935+2154: MAXI/GSC detection
  51. Fermi GBM trigger 488128598/160620637 is not a GRB
  52. Fermi GBM trigger 487974449/160618852 is not a GRB
  53. Trigger 689353 (possible transient near Sgr A*), Swift-BAT refined analysis
  54. Trigger 689353: Swift detection of a transient near Sgr A*
  55. Fermi GBM trigger 486562774/160602514 is not a GRB
  56. Another Swift detection of SGR 1935+2154 (trigger #687124)
  57. Swift detection of SGR 1935+2154
  58. Konus-Wind observation of a bright burst from SGR 1935+2154
  59. FERMI GBM bursts from the magnetar SGR 1935+2154
  60. SGR 1935+2154: AbAO optical upper limit
  61. Fermi GBM triggers of SGR 1935+2154
  62. Trigger 686761: Swift detection of a bright burst from SGR 1935+2154
  63. Fermi GBM trigger 485124591/160516868 is not a GRB
  64. Trigger 686443: Swift detection of SGR 1935+2154
  65. Fermi GBM trigger 484906918/160514349 is not a GRB
  66. GRB 160401A: a long GRB detected by INTEGRAL
  67. SGR 0755-2933, Swift-BAT refined analysis
  68. Swift detection of a likely new SGR: SGR 0755-2933
  69. IBAS Alert 7313 is SGR J1935+2154
  70. GRB 151221A: INTEGRAL detection of a short burst or possible SGR
  71. Swift-BAT refined analysis of trigger 664624 from SGR J1819-1600
  72. Swift-BAT probable detection of an outburst from SGR J1819-1600 (AX J1818.8-1559)
  73. LIGO/Virgo G184098: Fermi-GBM ground-based follow-up
  74. GRB 150912A: A long GRB detected by INTEGRAL
  75. SGR 1E 1841-045 (Swift trigger 649113): Terskol upper limit
  76. Fermi GBM triggers bn150715759 and bn150715817 are not due to GRBs
  77. Trigger 649113: Swift detection of SGR 1E 1841-045
  78. Swift-XRT observations of GRB 150710A
  79. Swift trigger 642453 is not an astrophysical source
  80. Konus-Wind observation of a bright burst from SGR 1935+2154
  81. IPN Triangulation of a bright burst from SGR 1935+2154
  82. GRB 150301A: Swift-BAT refined analysis
  83. GRB 150301A: Fermi GBM observation
  84. GRB 150301A: Swift detection of a short burst or new SGR
  85. Fermi GBM Observations of SGR 1935+2154
  86. Fermi GBM trigger 150223068 is not a GRB
  87. SGR 1935+2154: Swift-BAT refined analysis
  88. Swift detection of an outburst from SGR 1935+2154
  89. Trigger 607399: Swift detection of SGR1806-20
  90. Fermi GBM Observations of SGR 1935+2154
  91. GRB 140710B: a long GRB detected with INTEGRAL
  92. GRB 140705A / SGR 1935+2154: VLA 6 GHz observations
  93. Pre-discovery observations of SGR 1935+2154 in Swift archival data
  94. GRB 140705A / SGR 1935+2154: Probable association with supernova remnant G57.2+0.8
  95. SGR 1935+2154: Swift-BAT observations of additional short soft events
  96. GRB 140705A / SGR 1935+2154: FTN observations
  97. GRB 140705A / SGR 1935+2154: Optical observations from 10.4m GTC
  98. GRB 140705A: Swift-BAT refined analysis of a possible newly discovered SGR 1935+2154
  99. Swift detection of a bright X-ray source in M31
  100. Fermi GBM Trigger 140429551 - Detection of a burst from SGR 1806-20

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