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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.

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

20840 results found.

  1. LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
  2. GRB 240910A: radio detection with the VLA
  3. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  4. EP240919a: NOT and Gemini optical observations
  5. EP240919a: GOTO optical upper limits
  6. EP240919a: JinShan optical upper limits
  7. LIGO/Virgo/KAGRA S240920bz: Identification of a GW compact binary merger candidate
  8. LIGO/Virgo/KAGRA S240917cb: Updated Sky localization and EM Bright Classification
  9. LIGO/Virgo/KAGRA S240916ar: Updated Sky localization and EM Bright Classification
  10. EP240918b and EP240918c: EP-WXT detection of two fast X-ray transients
  11. GRB 240910A: further Swift observations and confirmation of afterglow
  12. LIGO/Virgo/KAGRA S240919bn: Identification of a GW compact binary merger candidate
  13. EP240918a: JinShan optical upper limits
  14. EP240918a: Optical upper limits with Kinder observations
  15. EP240918a: GMG Optical Upper Limit
  16. EP240918a: an X-ray transient detected by Einstein Probe
  17. GRB 240916A: NOT optical observation
  18. IPN triangulation of GRB 240913C / EP 240913a
  19. LIGO/Virgo/KAGRA S240917cb: Identification of a GW compact binary merger candidate
  20. GRB 240821A: radio observation with the VLA
  21. GRB 240916A: Swift-XRT afterglow detection
  22. LIGO/Virgo/KAGRA S240916ar: Identification of a GW compact binary merger candidate
  23. LIGO/Virgo S240915b: Swift XRT observations, 8 X-ray sources
  24. GRB 240916A: GOTO identification of two new optical sources within the GBM localisation region
  25. EP240913a: VLT/HAWK-I near-infrared upper limits
  26. LIGO/Virgo/KAGRA S240915bd: Identification of a GW compact binary merger candidate
  27. LIGO/Virgo/KAGRA S240915b: Updated Sky localization and EM Bright Classification
  28. LIGO/Virgo/KAGRA S240915b: Identification of a GW compact binary merger candidate
  29. GRB 240914A: Swift-XRT observations
  30. GRB 240910A: SVOM/VT optical observations
  31. EP240913a: NOT optical upper limits
  32. EP240913a: JinShan optical upper limits
  33. EP240913a: ESO-NTT optical observations
  34. GRB 240914A: ESO-NTT optical observations
  35. GRB 240905E: further NOT optical observations
  36. EP240913a: EP-WXT detection of a fast X-ray transient
  37. GRB 240911A: LCO optical observations
  38. GRB 240911A: JinShan optical upper limits on two Swift/XRT candidates
  39. GRB 240912A: Swift/UVOT Detection
  40. GRB 240911A: Swift-XRT observations
  41. GRB 240912A: J-band observations with WINTER
  42. GRB 240912A: LCOGT detection and Legacy Surveys likely host galaxy
  43. GRB 240912A: Enhanced Swift-XRT position
  44. GRB 240912A: Redshift from OSIRIS+/GTC
  45. Fast X-ray Transient EP240801a: GMRT radio observations
  46. GRB 240910A: Redshift from OSIRIS+/GTC
  47. GRB 240912A: Swift detection of a burst with an optical counterpart
  48. GRB 240910A: JinShan optical observations
  49. IPN triangulation of GRB 240905B (short)
  50. GRB 240825A: 7DT Optical Upper Limit
  51. GRB 240905E: SVOM/VT optical observations
  52. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  53. LIGO/Virgo/KAGRA S240910ci: Updated Sky localization and EM Bright Classification
  54. LIGO/Virgo/KAGRA S240910ci: Identification of a GW compact binary merger candidate
  55. GRB 240910A: SVOM/GRM observation
  56. EP240908a: Mondy and AbAO follow-up observations
  57. EP240908a: TRT optical upper limit
  58. EP240908a: EP detection of a fast X-ray transient
  59. LIGO/Virgo/KAGRA S240908dg: Identification of a GW compact binary merger candidate
  60. LIGO/Virgo/KAGRA S240908bs: Identification of a GW compact binary merger candidate
  61. LIGO/Virgo/KAGRA S240907cg: Identification of a GW compact binary merger candidate
  62. GRB 240905E: GIT optical upper limit
  63. GRB 240905B: Swift-XRT observations
  64. GRB 240905E: Gaoyazi/GOT optical upper limits
  65. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  66. GRB 240905B: Fermi-LAT detection
  67. GRB 240905E: J-band observations with WINTER
  68. GRB 240905E: CrAO Optical Afterglow observations, possible OT candidate
  69. GRB 240905E: AKO Optical Upper Limit
  70. GRB 240905E: SVOM/C-GFT optical upper limit
  71. GRB 240905E: OHP/MISTRAL T193 optical upper limit
  72. GRB 240905E: NOT optical upper limits
  73. GRB 240905E: REM optical/NIR upper limits
  74. GRB 240902B: AstroSat CZTI detection of a long burst
  75. GRB 240905E: LCOGT Optical Upper Limit
  76. GRB 240905E: Swift/UVOT Upper Limits
  77. GRB 240905E: SAO RAS optical upper limit
  78. GRB 240905E: Nanshan/HMT optical upper limit
  79. GRB 240905E: Swift detection of a burst
  80. GRB 240819A: Optical upper limits from TESS
  81. GRB 240904A: Swift detection of a burst
  82. LIGO/Virgo/KAGRA S240902bq: Identification of a GW compact binary merger candidate
  83. GRB 240825A: MeerLICHT afterglow detection
  84. GRB 240828A: SAO RAS AS-500(2) optical observations
  85. GRB 240825A: TSHAO Optical Upper Limit
  86. GRB240828B: REM optical/NIR upper limits
  87. GRB 240828B: AbAO optical upper limit
  88. GRB 240825A: SOAR observations
  89. GRB 240828B: Mephisto optical upper limit
  90. GRB 240828B: GRANDMA Optical Upper Limit
  91. LIGO/Virgo/KAGRA S240830gn: Updated Sky localization and EM Bright Classification
  92. LIGO/Virgo/KAGRA S240830gn: Identification of a GW compact binary merger candidate
  93. GRB 240825A: MeerKAT detection
  94. GRB 240828B: J-band upper limit from WINTER
  95. GRB 240828B: GMG Optical Upper Limit
  96. GRB 240828B: SVOM/C-GFT optical upper limit
  97. GRB 240828B: SAO RAS optical upper limit
  98. GRB 240828A: SAO RAS optical observations
  99. GRB 240629A: First GRB Detected by BurstCube
  100. GRB 240828A: KAIT Optical Afterglow Candidate

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