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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"

24705 results found.

  1. LIGO/Virgo/KAGRA S241230bd: Upper limits from Swift/BAT-GUANO
  2. GRB 250101A: Swift-BAT refined analysis
  3. GRB 250101A: further SAO RAS optical observations
  4. GRB 250101A: LCO optical counterpart detection
  5. GRB 250101A NUTTelA-TAO / BSTI Early Measurements
  6. GRB 250101A: Swift/UVOT Detection
  7. GRB 250101A: 1.6m Mephisto multi-band optical followup
  8. GRB 250101A: Swift-XRT refined Analysis
  9. GRB 250101A: Montarrenti Observatory optical observations and rebrightening
  10. GRB 250101A: LCOGT optical afterglow detection
  11. GRB 250101A: OASDG optical observations
  12. GRB 250101B: Fermi GBM Final Real-time Localization
  13. GRB 250101A: SAO RAS observations of optical brightening
  14. GRB 250101A: BOOTES-4/MET optical afterglow detection
  15. GRB 250101A: AKO Optical Afterglow Detection
  16. GRB 250101A: SAO RAS optical observations
  17. GRB 250101A: Enhanced Swift-XRT position
  18. LIGO/Virgo/KAGRA S250101k: Updated Sky localization and Source Classification
  19. GRB 250101A: SVOM/C-GFT early optical observations
  20. LIGO/Virgo/KAGRA S250101k: Upper limits from Fermi-GBM Observations
  21. GRB 250101A: Nanshan/HMT optical observations
  22. GRB 250101A : GIT optical detection
  23. GRB 250101A: GMG Optical Observation
  24. GRB 250101A: Swift detection of a burst with an optical counterpart
  25. LIGO/Virgo/KAGRA S241231du: Coverage and upper limit from MAXI/GSC observations
  26. LIGO/Virgo/KAGRA S250101k: Identification of a GW compact binary merger candidate
  27. GRB 241229B: Continued CrAO ZTSh observations
  28. LIGO/Virgo/KAGRA S241231bg: Updated NED Galaxies in the Localization Volume
  29. LIGO/Virgo/KAGRA S241231bg: Updated Sky localization and EM Bright Classification
  30. LIGO/Virgo/KAGRA S241230ev: Updated Sky localization
  31. LIGO/Virgo/KAGRA S241231bg: NED Galaxies in the Localization Volume
  32. LIGO/Virgo/KAGRA S241230bd: Updated Sky localization
  33. GRB 241228B: Multiband optical monitoring with 1.6m Mephisto
  34. GRB 241229B: SVOM/GRM observation
  35. LIGO/Virgo/KAGRA S241231bg: Identification of a GW compact binary merger candidate
  36. EP241217A: J band upper limit by SYSU 80cm telescope
  37. LIGO/Virgo/KAGRA S241230ev: Identification of a GW compact binary merger candidate
  38. GRB 241229B: SAO RAS optical upper limit
  39. GRB 241228B: SAO RAS optical observations
  40. GRB 241229A: SAO RAS optical observations
  41. IceCube-Cascade 241228A: Upper limits from a search for additional neutrino events in IceCube
  42. GRB 241229A: Swift-XRT observations
  43. EP240702a: 7DT Optical upper limits
  44. GRB 240606B: 7DT Optical upper limits
  45. LIGO/Virgo/KAGRA S241230bd: Identification of a GW compact binary merger candidate
  46. GRB 241229B: Swift-BAT refined analysis
  47. LIGO/Virgo/KAGRA S241225v: Updated Sky localization
  48. LIGO/Virgo/KAGRA S241225c: Updated Sky localization and EM Bright Classification
  49. GRB241229B: UVOT upper limits
  50. GRB 241228B: Fermi GBM Observation
  51. GRB 241228B: Swift-XRT afterglow detection
  52. GRB 241229B: Fermi GBM Observation
  53. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  54. GRB 241228A: Mondy optical afterglow observations
  55. GRB 241229A: GOTO optical upper limits
  56. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  57. GRB 241228A: NOT optical upper limits
  58. GRB 241228B: LCO optical observation
  59. GRB 241228A: Swift-BAT refined analysis
  60. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  61. GRB 241228A: Fermi GBM Observation
  62. GRB241228B: GROWTH-India Telescope optical observations
  63. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  64. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  65. GRB 241228A: GROWTH-India telescope optical upper limit
  66. GRB 241228B: TRT optical counterpart confirmation
  67. GRB 241228A: Swift-XRT refined Analysis
  68. GRB 241228A: Swift/UVOT Upper Limits
  69. GRB 241228A: Enhanced Swift-XRT position
  70. GRB 241228A: Swift detection of a burst
  71. IceCube-241224A: Upper limits from a search for additional neutrino events in IceCube
  72. LIGO/Virgo/KAGRA S241225c: Two counterpart neutrino candidates from IceCube neutrino searches
  73. GRB 241212A: VZLUSAT-2 detection
  74. EP241223a: Mondy AZT-33IK optical observations
  75. GRB 241029A: LCO optical observation
  76. GRB 241223A: Swift-XRT observations
  77. LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
  78. GRB 241029A: AbAO AS-32 optical observations
  79. GRB 241223A: Fermi GBM Detection
  80. Fermi trigger No 756678579: Global MASTER-Net observations report
  81. LIGO/Virgo/KAGRA S241225c: Identification of a GW compact binary merger candidate
  82. EP241223a
  83. EP241223a: EP-WXT detection of a fast X-ray transient
  84. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  85. GRB241113A: 7DT Optical upper limits
  86. GRB 241223A: GOTO optical observations summary
  87. GRB 241105A: JWST photometric observations of the host galaxy
  88. EP241217a: e-MERLIN radio observations
  89. GRB 241223A: BALROG localization (Fermi Trigger 756648531 / GRB 241223506)
  90. The EP-WXT trigger 01709129287 is likely a flaring star
  91. EP241217a: Liverpool Telescope optical upper limit
  92. EP241021a: VLA radio detection
  93. GRB 241218A: Mondy AZT-33IK optical upper limit
  94. EP241217a : Leavitt Observatory optical upper limit
  95. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  96. EP241217a: 1.6m Mephisto multi-band optical observations
  97. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  98. GRB 241218A: Swift/UVOT Upper Limits
  99. EP241217a: optical upper limit with the Liverpool Telescope
  100. GRB 241209B: EP-FXT afterglow detection

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