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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"

45415 results found.

  1. GRB 241206A: Swift/BAT-GUANO localization skymap of a burst
  2. GRB 241206B: SVOM/MXT observations: a probable flare from the QSO 1ES 1959+650
  3. GRB 241206B: GWAC-F50A optical upper limit
  4. GRB 241206B: SVOM/ECLAIRs detection of a long soft transient
  5. EP241113a: Keck/LRIS spectroscopic observation and tentative redshift
  6. Fermi GRB 241206A: Global MASTER-Net observations report
  7. GRB 241206A: Fermi GBM Final Real-time Localization
  8. EP241201a: 1.6m Mephisto Optical Upper Limits
  9. GRB 241204A: COLIBRÍ Optical Upper Limit
  10. EP241202b: KAIT optical upper limit
  11. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  12. GRB 241204A: DDOTI Upper Limits on the Afterglow
  13. GRB 241204A: Fermi GBM Observation
  14. Fermi GRB 241204A: Global MASTER-Net observations report
  15. GRB 241130A: CALET Gamma-Ray Burst Monitor detection
  16. GRB 241128A : RAPAS follow-up observations
  17. GRB 241201A: GRBAlpha detection
  18. GRB 241204A: Fermi-LAT detection
  19. EP241202b: Upper limits from Fermi-GBM Observations
  20. IceCube-241127A: No transient candidates from the Zwicky Transient Facility
  21. EP241202b: Kinder optical counterpart candidate
  22. Fermi-GBM Sub-Threshold Detection of GRB 241128A
  23. GRB 241113B : RAPAS follow-up observation
  24. EP241201a: EP-FXT follow-up observations
  25. Konus-Wind detection of GRB 241130A
  26. EP241202b: Global MASTER-Net observations report
  27. EP241201a: BOOTES-5 optical upper limit
  28. EP241202b: EP detection of a fast X-ray transient
  29. EP241201a: NOT optical observations
  30. IPN triangulation of GRB 241130A
  31. GRB 241130A: EIRSAT-1 GMOD Detection
  32. GRB 241128A: Swift/UVOT Upper Limits
  33. GRB 241130A: Fermi GBM Detection
  34. IceCube-241127A: Upper limits from a search for additional neutrino events in IceCube
  35. GRB 241129A: Swift/BAT-GUANO localization skymap of a burst
  36. EP241201a: Kinder optical counterpart candidate
  37. LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
  38. EP241201a: Global MASTER-Net observations report
  39. EP241201a: EP detection of a fast X-ray transient
  40. The EP-WXT trigger 01709126243 is not a real source
  41. GRB 241127B: detection of a long GRB by SVOM/ECLAIRs
  42. GRB241201B: Fermi GBM Final Localization
  43. GRB241201B: Fermi GBM Final Localization
  44. LIGO/Virgo/KAGRA S241201ac: Updated Sky localization
  45. EP241126a: SOAR observations of the optical counterpart
  46. Fermi GRB 241201A: Global MASTER-Net observations report
  47. GRB 241201A: BALROG localization (Fermi Trigger 754757764 / GRB 241201622)
  48. GRB 241130A: Fermi GBM Final Real-time Localization
  49. GRB 241130A: Fermi GBM Final Real-time Localization
  50. EP241126a: 1.6m Mephisto Optical Upper Limits
  51. GRB 241201A: Fermi GBM Final Real-time Localization
  52. LIGO/Virgo/KAGRA S241201ac: Identification of a GW compact binary merger candidate
  53. LIGO/Virgo/KAGRA S241130be: Updated Sky localization
  54. Fermi trigger No 754701230: Global MASTER-Net observations report
  55. IPN triangulation of GRB 241128B
  56. Konus-Wind detection of GRB 241114B
  57. LIGO/Virgo/KAGRA S241130n: Updated Sky localization
  58. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  59. GRB 241128A: AbAO optical upper limit
  60. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  61. LIGO/Virgo/KAGRA S241130be: Identification of a GW compact binary merger candidate
  62. LIGO/Virgo/KAGRA S241129aa: Updated Sky localization
  63. LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
  64. SVOM/GRM observation of a short burst from soft gamma repeater Kes 73
  65. GRB 241128C: SVOM/GRM observation
  66. GRB 241128B: SVOM/GRM observation
  67. GRB 241128A: Swift-BAT refined analysis
  68. GRB 241127A: Swift-BAT refined analysis
  69. EP241126a: NOT optical observations
  70. GRB 241127A: PRIME near-infrared detection
  71. GRB 241128A: Mondy optical observations
  72. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  73. Swift-XRT observations of IceCube -241127A
  74. Swift GRB 241128A: Global MASTER-Net observations report
  75. Fermi-LAT gamma-ray observations of IceCube-241127A
  76. EP241126a: SVOM/VT observations
  77. LIGO/Virgo/KAGRA S241129aa: Identification of a GW compact binary merger candidate
  78. GRB 241128A: Swift-XRT refined Analysis
  79. GRB 241129A: Fermi GBM Final Real-time Localization
  80. GRB 241128A: Enhanced Swift-XRT position
  81. GRB 241128A: NOT optical observations
  82. GRB 241128A: LCO optical detection
  83. GRB 241128A: 1.5m OSN optical afterglow detection
  84. LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
  85. Fermi trigger No 754492985: Global MASTER-Net observations report
  86. GRB 241128A: Swift-XRT afterglow detection
  87. GRB 241128A: Swift detection of a burst
  88. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  89. GRB 241127A: Swift/UVOT Detection
  90. GRB 241127A: Swift-XRT refined Analysis
  91. GRB 241127A: SVOM/GRM observation
  92. GRB 241127A: Enhanced Swift-XRT position
  93. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  94. The EP-WXT trigger 01709125191 is not a real source
  95. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  96. Swift GRB241127.91: Global MASTER-Net OT detection
  97. EP241126a: WFST Observations
  98. LIGO/Virgo/KAGRA S241125n: Update on Coincidence False Alarm Method
  99. IceCube Alert 241127.59: Global MASTER-Net observations report
  100. GRB 241127A: Swift detection of a burst with an optical counterpart

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