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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"

44274 results found.

  1. GRB 241113B: SVOM/GRM observation
  2. EP241113a: EP on-board trigger and autonomous follow-up observation
  3. LIGO/Virgo/KAGRA S241114y: Identification of a GW compact binary merger candidate
  4. GRB 241113A: Swift-XRT refined Analysis
  5. EP241107a: SOAR upper limits
  6. GRB 241113A: Swift/UVOT Detection
  7. GRB 241113A: REM detection of the optical/NIR afterglow
  8. Konus-Wind detection of GRB 241107A (short/hard)
  9. LIGO/Virgo/KAGRA S241113p: Identification of a GW compact binary merger candidate
  10. Fermi Gamma-ray Burst Monitor trigger 753166198/241113201 is not a GRB
  11. GRB 241113B: Swift ToO observations
  12. GRB 241113A: LCO optical observations
  13. IceCube-241113A - IceCube observation of a high-energy neutrino candidate track-like event
  14. GRB 241112B: GMG Optical Upper Limit
  15. GRB 241113A: Enhanced Swift-XRT position
  16. GRB241113A: LCOGT (40-cm) optical counterpart detection
  17. GRB 241113B : detection of a long GRB by SVOM/ECLAIRs
  18. GRB 241113A: MASTER010615.66-224018.2 optical counterpart detection
  19. GRB 241113A: Swift detection of a burst with an optical counterpart
  20. Swift GRB241113.33: Global MASTER-Net observations report
  21. SVOM/GRM detection of a short burst from SGR 1E1841-045
  22. Fermi trigger No 753166198: Global MASTER-Net observations report
  23. LIGO/Virgo/KAGRA S241111bn: Updated Sky localization
  24. GRB 241105A: ATCA Radio Upper Limits
  25. GRB 241112B: AbAO optical upper limit
  26. GRB 241107A: GROWTH-India telescope optical upper limit
  27. IceCube Alert 241113.02: Global MASTER-Net observations report
  28. Fermi GRB 241112A: Global MASTER-Net observations report
  29. Fermi-GBM Sub-Threshold Detection of GRB 241112B
  30. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  31. GRB 241112B: Swift-XRT afterglow detection
  32. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  33. GRB 241112B: SVOM/GRM observation
  34. GRB 241112B: SVOM/VT afterglow detection
  35. Fermi Gamma-ray Burst Monitor trigger 752995908/241111230 (GRB 241111A) is not a GRB
  36. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  37. GRB 241112B: Mephisto optical upper limits
  38. GRB 241112B: GOTO optical upper limits
  39. GRB 241112B: Swift ToO observations
  40. GRB 241112B : detection of a long GRB by SVOM/ECLAIRs
  41. GRB 241107A: INTEGRAL IBIS localization
  42. EP241107a: EP-FXT follow-up observations
  43. GRB 241112A: Fermi GBM Final Real-time Localization
  44. LIGO/Virgo/KAGRA S241110br: NED Galaxies in the Localization Volume
  45. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  46. GRB 241105A: VLT/FORS2 refined spectroscopic redshift z = 2.681
  47. LIGO/Virgo/KAGRA S241111bn: Identification of a GW compact binary merger candidate
  48. IPN triangulation of GRB 241107A (short/hard)
  49. GRB 241107A: INTEGRAL/IBIS/PICsIT detection of a short burst
  50. GRB 241025C: VZLUSAT-2 detection
  51. GRB 241025A: VZLUSAT-2 detection
  52. GRB 241018A: cubesat Avion detection
  53. Fermi trigger No 752990530: Global MASTER-Net observations report
  54. GRB 241111A: Fermi GBM Final Real-time Localization
  55. GRB 241030B: TESS detection of optical counterpart
  56. LIGO/Virgo/KAGRA S241110br: Updated Sky localization
  57. LIGO/Virgo/KAGRA S241110bk: 1 counterpart neutrino candidate event from an IceCube neutrino search
  58. LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate
  59. LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations
  60. Fermi trigger No 752878030: Global MASTER-Net observations report
  61. Integral GRB241109.89: Global MASTER-Net observations report
  62. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  63. EP241109a: KAIT photometry and 3 m Shane spectroscopy from Lick observatory
  64. LIGO/Virgo/KAGRA S241109bn: Updated Sky localization and EM Bright Classification
  65. INTEGRAL detection of a burst from 1E 1841-045
  66. EP241107a: AbAO optical upper limit
  67. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  68. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  69. LIGO/Virgo/KAGRA S241109p: Updated Sky localization and Source Classification
  70. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  71. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  72. EP241109a: confirmation of a stellar flare by BOOTES-7
  73. EP241109a: EP on-board trigger and autonomous follow-up observation
  74. GRB 241108A: Swift-XRT observations
  75. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  76. EP241107A: MASTER optical observations of xray transient
  77. EP241107a: KAIT optical observations
  78. GRB 241108A: Swift ToO observations
  79. GRB 241030A: TESS observations
  80. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  81. GRB 241108A : a likely weak long GRB detected by SVOM/ECLAIRs
  82. EP241107a: Kinder optical follow-up observations
  83. GRB 241025A: radio detection with the VLA
  84. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  85. EP241107a: AKO Optical Afterglow Follow-Up Observations
  86. EP241107a: GSP detects optical counterpart
  87. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  88. GRB 241107A: SVOM/GRM detection of a short burst
  89. GRB 241105A: EP-FXT follow-up observations
  90. GRB 241105A: SVOM/GRM observation
  91. EP241107a: OHP/T193 photometric and spectroscopic observations
  92. GRB 241105a: PRIME near-infrared upper limits
  93. EP241107a: FTW Optical and NIR observations of the optical counterpart
  94. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  95. EP241107a: GIT optical observations
  96. EP241107a: Global MASTER-Net observations report
  97. EP241107a: SVOM/C-GFT optical observations
  98. EP241107a: AKO Optical Afterglow Detection
  99. GRB 241025A: LBT optical observations
  100. GRB241105A: Gemini-South Optical Afterglow Detection

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