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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"

32501 results found.

  1. GRB 240825A: LBT optical observations
  2. Fermi GRB 240930A: Global MASTER-Net observations report
  3. Fermi Gamma-ray Burst Monitor trigger 749362078/240930172 (GRB 240930A) is not a GRB
  4. LIGO/Virgo/KAGRA S240930aa: Identification of a GW compact binary merger candidate
  5. GRB 240929A long GRB detected by INTEGRAL
  6. Fermi GRB 240929A: Global MASTER-Net observations report
  7. Konus-Wind detection of GRB 240912A
  8. EP trigger ID 01709059262: Lick/Kast spectroscopy with 3 m Shane telescope
  9. NuEm-240926A / IC240926A: BZQJ0955+4532 ~0.6m optical decay and rebrightening detection by MASTER
  10. Konus-Wind detection of GRB 240905B
  11. GRB 240529A: FRAM-ORM early optical afterglow observations reveal plateau and rebrightening
  12. EP240919a / GRB 240919A: SVOM/VT upper limit
  13. EP240918b and EP240918c: EP-FXT follow-up observations
  14. LIGO/Virgo/KAGRA S240925n: Updated Sky localization and Source Classification
  15. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  16. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  17. LIGO/Virgo/KAGRA S240925n: Identification of a GW compact binary merger candidate
  18. Konus-Wind detection of GRB 240918B
  19. IPN triangulation of GRB 240918B
  20. GRB 240905B: VZLUSAT-2 detection
  21. LIGO/Virgo/KAGRA S240922df: Updated Sky localization
  22. LIGO/Virgo/KAGRA S240920dw: Updated Sky localization
  23. LIGO/Virgo/KAGRA S240921cw: Updated Sky localization
  24. LIGO/Virgo/KAGRA S240924a: Updated Sky localization
  25. LIGO/Virgo/KAGRA S240920bz: Updated Sky localization and Source Classification
  26. LIGO/Virgo/KAGRA S240923ct: Updated Sky localization and Source Classification
  27. EP trigger ID 01709059262: correction to the observation start time and source localization
  28. LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
  29. LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
  30. LIGO/Virgo S240919bn: GOTO optical upper limits
  31. GRB 240918B: AstroSat CZTI detection
  32. LIGO/Virgo/KAGRA S240922df: Identification of a GW compact binary merger candidate
  33. LIGO/Virgo/KAGRA S240921cw: Identification of a GW compact binary merger candidate
  34. EP240919a: EP-FXT follow-up observation update
  35. EP240913A/GRB 240913C: AbAO optical upper limit
  36. EP240919a / GRB 240919A: Mondy optical upper limit
  37. EP240913a/GRB 240913C: 1.6m Mephisto observations
  38. EP240918a: SVOM/VT upper limit
  39. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  40. EP240919a / GRB 240919A: REM optical and NIR upper limits
  41. EP240919a / GRB 240919A: KAIT optical upper limit
  42. EP240918b and EP240918c: Optical upper limits with Kinder observations
  43. GRB 240414A: further radio observations with the VLA
  44. EP240919a: Optical upper limit with Kinder observations
  45. GRB 240919A / EP240919a: SVOM/GRM observation
  46. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  47. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  48. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  49. EP EP240919a: Global MASTER-Net observations report
  50. GRB 240910A: radio detection with the VLA
  51. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  52. EP240919a: NOT and Gemini optical observations
  53. EP240919a: GOTO optical upper limits
  54. EP240919a: JinShan optical upper limits
  55. EP240919a is likely a GRB event (duplicate submission of 37563)
  56. EP240919a is likely a GRB event
  57. LIGO/Virgo/KAGRA S240920bz: Identification of a GW compact binary merger candidate
  58. GRB 240918A and GRB 240918B : INTEGRAL SPI ACS LIGHT CURVE
  59. LIGO/Virgo/KAGRA S240919bn: Updated Sky localization
  60. GRB 240918B: Fermi GBM Detection
  61. LIGO/Virgo/KAGRA S240917cb: Updated Sky localization and EM Bright Classification
  62. LIGO/Virgo/KAGRA S240916ar: Updated Sky localization and EM Bright Classification
  63. EP240918a: EP observation update
  64. GRB 240910A: further Swift observations and confirmation of afterglow
  65. LIGO/Virgo/KAGRA S240919bn: Identification of a GW compact binary merger candidate
  66. EP240918a: Swift-XRT observation
  67. Fermi GRB 240918A: Global MASTER-Net observations report
  68. EP EP240918a: Global MASTER-Net observations report
  69. EP240918a: JinShan optical upper limits
  70. EP240918a: YAHPT Optical Upper Limit
  71. EP240918a: Optical upper limits with Kinder observations
  72. EP240918a: GMG Optical Upper Limit
  73. GRB 240916A: GRBAlpha detection
  74. GRB 240914B: GRBAlpha detection
  75. GRB 240916A: NOT optical observation
  76. GRB 240912A: Swift-BAT refined analysis
  77. IPN triangulation of GRB 240913C / EP 240913a
  78. GRB 240825A: INTEGRAL SPI ACS LIGHT CURVE
  79. GRB 240825A: The nature of the afterglow motivates the search of the associated supernova
  80. GRB 240916A: Fermi GBM Observation
  81. LIGO/Virgo/KAGRA S240917cb: Identification of a GW compact binary merger candidate
  82. GRB 240821A: radio observation with the VLA
  83. GRB 240916A (AT 2024vlp / GOTO24fzn): VLT/X-shooter redshift
  84. GRB 240916A: Swift-XRT afterglow detection
  85. LIGO/Virgo/KAGRA S240916ar: Identification of a GW compact binary merger candidate
  86. GRB 240916A: Swift ToO observations
  87. GRB 240916A: JinShan optical decay in one of the two GOTO candidates
  88. GRB 240916A: GOTO identification of two new optical sources within the GBM localisation region
  89. EP EP240913a: Global MASTER-Net observations report
  90. LIGO/Virgo/KAGRA S240915b: Coverage and upper limits from MAXI/GSC observations
  91. GRB 240916A INTEGRAL SPI ACS LIGHT CURVE
  92. LIGO/Virgo/KAGRA S240915bd: Updated Sky localization
  93. EP240913a: VLT/HAWK-I near-infrared upper limits
  94. LIGO/Virgo/KAGRA S240915bd: Identification of a GW compact binary merger candidate
  95. LIGO/Virgo/KAGRA S240915b: Updated Sky localization and EM Bright Classification
  96. LIGO/Virgo/KAGRA S240915b: Identification of a GW compact binary merger candidate
  97. EP240913a/GRB 240913C: KAIT optical upper limit
  98. EP240913a / GRB 240913C INTEGRAL SPI ACS LIGHT CURVE
  99. GRB 240913C: Fermi GBM detection
  100. GRB 240913C: Joint location by ETJASMIN

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