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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"

31741 results found.

  1. GRB 241113B: SVOM/GRM observation
  2. LIGO/Virgo/KAGRA S241114y: Identification of a GW compact binary merger candidate
  3. EP241107a: SOAR upper limits
  4. GRB 241113A: Swift/UVOT Detection
  5. GRB 241113A: REM detection of the optical/NIR afterglow
  6. Konus-Wind detection of GRB 241107A (short/hard)
  7. LIGO/Virgo/KAGRA S241113p: Identification of a GW compact binary merger candidate
  8. GRB 241113B: Swift ToO observations
  9. GRB 241113A: LCO optical observations
  10. GRB 241112B: GMG Optical Upper Limit
  11. GRB241113A: LCOGT (40-cm) optical counterpart detection
  12. GRB 241113A: MASTER010615.66-224018.2 optical counterpart detection
  13. SVOM/GRM detection of a short burst from SGR 1E1841-045
  14. LIGO/Virgo/KAGRA S241111bn: Updated Sky localization
  15. GRB 241105A: ATCA Radio Upper Limits
  16. GRB 241112B: AbAO optical upper limit
  17. GRB 241107A: GROWTH-India telescope optical upper limit
  18. Fermi GRB 241112A: Global MASTER-Net observations report
  19. Fermi-GBM Sub-Threshold Detection of GRB 241112B
  20. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  21. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  22. GRB 241112B: SVOM/GRM observation
  23. GRB 241112B: SVOM/VT afterglow detection
  24. Fermi Gamma-ray Burst Monitor trigger 752995908/241111230 (GRB 241111A) is not a GRB
  25. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  26. GRB 241112B: Mephisto optical upper limits
  27. GRB 241112B: GOTO optical upper limits
  28. GRB 241112B: Swift ToO observations
  29. GRB 241107A: INTEGRAL IBIS localization
  30. EP241107a: EP-FXT follow-up observations
  31. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  32. GRB 241105A: VLT/FORS2 refined spectroscopic redshift z = 2.681
  33. LIGO/Virgo/KAGRA S241111bn: Identification of a GW compact binary merger candidate
  34. IPN triangulation of GRB 241107A (short/hard)
  35. GRB 241107A: INTEGRAL/IBIS/PICsIT detection of a short burst
  36. GRB 241025C: VZLUSAT-2 detection
  37. GRB 241025A: VZLUSAT-2 detection
  38. GRB 241018A: cubesat Avion detection
  39. GRB 241030B: TESS detection of optical counterpart
  40. LIGO/Virgo/KAGRA S241110br: Updated Sky localization
  41. LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate
  42. LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations
  43. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  44. EP241109a: KAIT photometry and 3 m Shane spectroscopy from Lick observatory
  45. LIGO/Virgo/KAGRA S241109bn: Updated Sky localization and EM Bright Classification
  46. EP241107a: AbAO optical upper limit
  47. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  48. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  49. LIGO/Virgo/KAGRA S241109p: Updated Sky localization and Source Classification
  50. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  51. EP241109a: confirmation of a stellar flare by BOOTES-7
  52. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  53. EP241107A: MASTER optical observations of xray transient
  54. EP241107a: KAIT optical observations
  55. GRB 241108A: Swift ToO observations
  56. GRB 241030A: TESS observations
  57. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  58. EP241107a: Kinder optical follow-up observations
  59. GRB 241025A: radio detection with the VLA
  60. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  61. EP241107a: AKO Optical Afterglow Follow-Up Observations
  62. EP241107a: GSP detects optical counterpart
  63. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  64. GRB 241105A: EP-FXT follow-up observations
  65. GRB 241105A: SVOM/GRM observation
  66. EP241107a: OHP/T193 photometric and spectroscopic observations
  67. GRB 241105a: PRIME near-infrared upper limits
  68. EP241107a: FTW Optical and NIR observations of the optical counterpart
  69. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  70. EP241107a: GIT optical observations
  71. EP241107a: Global MASTER-Net observations report
  72. EP241107a: SVOM/C-GFT optical observations
  73. EP241107a: AKO Optical Afterglow Detection
  74. GRB 241025A: LBT optical observations
  75. GRB241105A: Gemini-South Optical Afterglow Detection
  76. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  77. GRB 241105A: Swift/UVOT Detection
  78. EP241101a: CrAO ZTSH optical observations
  79. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  80. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  81. GRB 241030A: Mondy optical observations
  82. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  83. Konus-Wind detection of GRB 241105A (short with extended emission)
  84. Konus-Wind detection of GRB 241021A
  85. GRB 241105A: SVOM/VT optical afterglow observations
  86. GRB 241105A: Swift-XRT afterglow detection
  87. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  88. GRB 241104A: Swift-XRT observations
  89. GRB 240511A: LCO upper limits
  90. GRB 241104A: Fermi GBM Observation
  91. GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
  92. GRB 241105A: Swift ToO observations
  93. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  94. GRB 241104A: Swift ToO observations
  95. GRB 241104A: NOT optical non-detection
  96. GRB 241105A: GOTO tentative optical counterpart candidate
  97. Fermi GRB 241105A: Global MASTER-Net observations report
  98. GRB 241104A: SVOM/VT optical candidate
  99. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  100. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart

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