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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').
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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

32485 results found.

  1. LIGO/Virgo/KAGRA S241114y: Updated Sky localization
  2. Fermi GRB 241118A: Global MASTER-Net observations report
  3. Updates to IceCube realtime alert system for muon tracks
  4. GRB 241117A: SVOM/GRM observation of a short burst with extended emission
  5. Fermi GRB 241117B: Global MASTER-Net observations report
  6. LIGO/Virgo/KAGRA S241116cq: Updated Sky localization
  7. GRB 241115B: Swift/BAT-GUANO localization skymap of a long burst
  8. Fermi GRB 241117A: Global MASTER-Net observations report
  9. GRB 241115C: Fermi GBM Observation
  10. LIGO/Virgo/KAGRA S241116cq: Identification of a GW compact binary merger candidate
  11. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  12. GRB 241115A: Mephisto upper limits
  13. GRB 241113B: Mephisto upper limits
  14. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  15. GRB 241115D / EP 241115a: SVOM/GRM observation
  16. The EP-WXT trigger 01709120856 is likely a flaring star
  17. EP241113a: Swift XRT weak detection
  18. GRB 241115A: Fermi GBM Observation
  19. GRB 241115A: LCOGT Optical Upper Limits
  20. Fermi GRB 241115B: Global MASTER-Net observations report
  21. LIGO/Virgo/KAGRA S241114bi: Updated Sky localization and EM Bright Classification
  22. EP241115a: Global MASTER-Net observations report
  23. LIGO/Virgo/KAGRA S241113p: Updated Sky localization
  24. EP241113a: No Detection in Fermi-GBM Observations
  25. Swift GRB 241115A: Global MASTER-Net observations report
  26. Fermi GRB 241115A: Global MASTER-Net observations report
  27. EP 241113a: LBT possible optical counterpart
  28. GRB 241113B: KAIT Optical Afterglow Candidate
  29. LIGO/Virgo/KAGRA S241114bi: Upper limits from Fermi-GBM Observations
  30. GRB 241113A: Swift-BAT refined analysis
  31. LIGO/Virgo/KAGRA S241114bi: Identification of a GW compact binary merger candidate
  32. GRB 241113A: PRIME near-infrared upper limits
  33. Fermi GRB 241114A: Global MASTER-Net observations report
  34. EP241113a: Global MASTER-Net observations report
  35. GRB 241113B: J-band upper limit from WINTER
  36. GRB 241113A: J-band observations with WINTER
  37. EP241113a : J-band observations with WINTER
  38. GRB 241030A: LCO optical observation
  39. IceCube-241113A: Upper limits from a search for additional neutrino events in IceCube
  40. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  41. GRB 241113A: KAIT optical observations
  42. EP241113b: Global MASTER-Net observations report
  43. EP241113b/GRB 241113B: EP detection of GRB 241113B
  44. Fermi-LAT gamma-ray observations of IceCube-241113A
  45. GRB 241113B: SVOM/GRM observation
  46. LIGO/Virgo/KAGRA S241114y: Identification of a GW compact binary merger candidate
  47. EP241107a: SOAR upper limits
  48. GRB 241113A: Swift/UVOT Detection
  49. GRB 241113A: REM detection of the optical/NIR afterglow
  50. Konus-Wind detection of GRB 241107A (short/hard)
  51. LIGO/Virgo/KAGRA S241113p: Identification of a GW compact binary merger candidate
  52. GRB 241113B: Swift ToO observations
  53. GRB 241113A: LCO optical observations
  54. GRB 241112B: GMG Optical Upper Limit
  55. GRB241113A: LCOGT (40-cm) optical counterpart detection
  56. GRB 241113A: MASTER010615.66-224018.2 optical counterpart detection
  57. SVOM/GRM detection of a short burst from SGR 1E1841-045
  58. LIGO/Virgo/KAGRA S241111bn: Updated Sky localization
  59. GRB 241105A: ATCA Radio Upper Limits
  60. GRB 241112B: AbAO optical upper limit
  61. GRB 241107A: GROWTH-India telescope optical upper limit
  62. Fermi GRB 241112A: Global MASTER-Net observations report
  63. Fermi-GBM Sub-Threshold Detection of GRB 241112B
  64. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  65. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  66. GRB 241112B: SVOM/GRM observation
  67. GRB 241112B: SVOM/VT afterglow detection
  68. Fermi Gamma-ray Burst Monitor trigger 752995908/241111230 (GRB 241111A) is not a GRB
  69. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  70. GRB 241112B: Mephisto optical upper limits
  71. GRB 241112B: GOTO optical upper limits
  72. GRB 241112B: Swift ToO observations
  73. GRB 241107A: INTEGRAL IBIS localization
  74. EP241107a: EP-FXT follow-up observations
  75. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  76. GRB 241105A: VLT/FORS2 refined spectroscopic redshift z = 2.681
  77. LIGO/Virgo/KAGRA S241111bn: Identification of a GW compact binary merger candidate
  78. IPN triangulation of GRB 241107A (short/hard)
  79. GRB 241107A: INTEGRAL/IBIS/PICsIT detection of a short burst
  80. GRB 241025C: VZLUSAT-2 detection
  81. GRB 241025A: VZLUSAT-2 detection
  82. GRB 241018A: cubesat Avion detection
  83. GRB 241030B: TESS detection of optical counterpart
  84. LIGO/Virgo/KAGRA S241110br: Updated Sky localization
  85. LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate
  86. LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations
  87. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  88. EP241109a: KAIT photometry and 3 m Shane spectroscopy from Lick observatory
  89. LIGO/Virgo/KAGRA S241109bn: Updated Sky localization and EM Bright Classification
  90. EP241107a: AbAO optical upper limit
  91. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  92. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  93. LIGO/Virgo/KAGRA S241109p: Updated Sky localization and Source Classification
  94. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  95. EP241109a: confirmation of a stellar flare by BOOTES-7
  96. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  97. EP241107A: MASTER optical observations of xray transient
  98. EP241107a: KAIT optical observations
  99. GRB 241108A: Swift ToO observations
  100. GRB 241030A: TESS observations

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