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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"

22062 results found.

  1. Fermi GRB 230603A: Global MASTER-Net observations report
  2. Fermi trigger No 707039690: Global MASTER-Net observations report
  3. ZTF and GIT Observations of the Candidate Optical Afterglow AT2023jxk
  4. LIGO/Virgo/KAGRA S230602ap: Zwicky Transient Facility observations
  5. GRB 230606A: Swift/UVOT Upper Limits
  6. LIGO/Virgo S230606z: Global MASTER-Net observations report
  7. LIGO/Virgo S230606d: Global MASTER-Net observations report
  8. Fermi-LAT gamma-ray observations of IceCube-230603A
  9. LIGO/Virgo S230605o: Global MASTER-Net observations report
  10. LIGO/Virgo S230604z: Global MASTER-Net observations report
  11. LIGO/Virgo S230603aa: Global MASTER-Net observations report
  12. LIGO/Virgo S230602ap: Global MASTER-Net observations report
  13. LIGO/Virgo S230601bf: Global MASTER-Net observations report
  14. LIGO/Virgo S230531f: Global MASTER-Net observations report
  15. LIGO/Virgo/KAGRA S230529ay: Zwicky Transient Facility observations
  16. LIGO/Virgo/KAGRA S230528a: Zwicky Transient Facility observations
  17. LIGO/Virgo/KAGRA S230527ch: Zwicky Transient Facility observations
  18. LIGO/Virgo/KAGRA S230529ay: Upper limits from CALET observations.
  19. LIGO/Virgo S230529ay: Global MASTER-Net observations report
  20. LIGO/Virgo/KAGRA S230529ay: Coverage and upper limits from MAXI/GSC observations
  21. LIGO/Virgo/KAGRA S230529ay: Upper limits from Fermi-GBM Observations
  22. LIGO/Virgo/KAGRA S230529ay: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  23. LIGO/Virgo S230529p: Global MASTER-Net observations report
  24. Alert from the HAWC Burst Monitor HAWC-230527A
  25. LIGO/Virgo S230525a: Global MASTER-Net observations report
  26. Fermi-LAT gamma-ray observations of IceCube-230524A
  27. LIGO/Virgo/KAGRA S230518h: Upper limits from Glowbug gamma-ray observations
  28. LIGO/Virgo/KAGRA S230518h: TESS observations of the localization region
  29. IceCube Alert 230524.47: Global MASTER-Net observations report
  30. LIGO/Virgo/KAGRA S230518h: No transient candidates in CALET observations
  31. Fermi trigger No 706610076: Global MASTER-Net observations report
  32. LIGO/Virgo S230524b: Global MASTER-Net observations report
  33. Fermi trigger No 706599831: Global MASTER-Net observations report
  34. Fermi trigger No 706536788: Global MASTER-Net observations report
  35. LIGO/Virgo/KAGRA S230521k: MASTER new OT discovery
  36. GRB 230523A: Swift/BAT-GUANO detection of a short hard burst
  37. LIGO/Virgo/KAGRA S230521k: Additional candidates from Zwicky Transient Facility
  38. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-230523A
  39. LIGO/Virgo S230522n: Global MASTER-Net observations report
  40. LIGO/Virgo S230522a: Global MASTER-Net observations report
  41. LIGO/Virgo/KAGRA S230518h: Swift/UVOT Upper Limits for MeerLICHT candidates: AT2023ixg and AT2023iyb
  42. LIGO/Virgo S230521k: Global MASTER-Net observations report
  43. LIGO/Virgo/KAGRA S230521k: Zwicky Transient Facility observations
  44. LIGO/Virgo S230520ae: Global MASTER-Net observations report
  45. Fermi trigger No 706328428: Global MASTER-Net observations report
  46. Fermi trigger No 706331483: Global MASTER-Net observations report
  47. Fermi trigger No 706317104: Global MASTER-Net observations report
  48. LIGO/Virgo/KAGRA S230518h: ATCA follow-up of candidate counterparts
  49. LIGO/Virgo/KAGRA S230518h: GECKO tiling observations with KMTNet
  50. LIGO/Virgo/KAGRA S230518h: Swift/UVOT Upper Limits for Swope candidates: SSS23a, SSS23b and SSS23c
  51. LIGO/Virgo/KAGRA S230518h: ATLAS observations of the skymap
  52. LIGO/Virgo/KAGRA S230518h: Swope Search and Candidate Counterpart Identification
  53. LIGO/Virgo/KAGRA S230518h: Upper limits from Konus-Wind observations
  54. LIGO/Virgo S230518h: AGILE/MCAL observations
  55. GRB 230518A: Swift/BAT-GUANO detection
  56. LIGO/Virgo S230518h: Swift XRT observations, 8 X-ray sources
  57. LIGO/Virgo/KAGRA S230518h: Coverage and upper limits from MAXI/GSC observations
  58. LIGO/Virgo/Kagra S230518h: NED Galaxies in the Localization Volume
  59. LIGO/Virgo/KAGRA S230518h: Upper limits from Fermi-GBM Observations
  60. LIGO/Virgo S230518h: Global MASTER-Net observations report
  61. GRB 230513A: Zwicky Transient Facility continuous observations of a Fermi Short GRB (Trigger 705709044)
  62. Fermi trigger No 706014351: Global MASTER-Net observations report
  63. Fermi trigger No 705952199: Global MASTER-Net observations report
  64. GRB 230512A: Liverpool Telescope observations
  65. GRB 230512A: GIT non detection of afterglow candidate
  66. Fermi trigger No 705565670: Global MASTER-Net observations report
  67. Fermi-LAT gamma-ray observations of IceCube-230511A
  68. GRB 230510A: OHP/T193 and OHP/T120 optical observations
  69. GRB 230512A: Swift-XRT observations
  70. GRB 230512A: GIT optical follow-up ZTF candidates
  71. GRB 230430A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 704533643)
  72. GRB 230511D: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705537623)
  73. GRB 230512A: Tiled Swift observations
  74. GRB 230510A: GIT optical upper limits
  75. GRB 230510A: Swift/UVOT Observations
  76. Fermi trigger No 705503315: Global MASTER-Net observations report
  77. Fermi trigger No 705496510: Global MASTER-Net observations report
  78. Fermi trigger No 705446499: Global MASTER-Net observations report
  79. GRB 230510A: Gaoyazi/GOT optical upper limit
  80. GRB 230510A: Nanshan/NEXT optical afterglow detection
  81. Fermi trigger No 705413051: Global MASTER-Net observations report
  82. GRB 230506C: SAO RAS optical observations
  83. GRB 230307A: JWST second-epoch observations
  84. Fermi-LAT gamma-ray observations of IceCube-230506A
  85. GRB 230506C: spectro-imaging observations of the optical afterglow with T193-OHP
  86. GRB 230506C: Swift/UVOT Upper Limits
  87. GRB 230506C: NUTTelA-TAO / BSTI Early Optical Limits
  88. GRB 230506C: Candidate afterglow observation by D50
  89. GRB 230506B: Swift/UVOT Detection
  90. Swift GRB230506.71: Global MASTER-Net observations report
  91. GRB 230506B: MASTER optical observations
  92. Fermi trigger No 704837952: Global MASTER-Net observations report
  93. GRB 230427A: NOT optical upper limit
  94. GRB 230427A: Swift/UVOT Detection
  95. GRB 230427A: Gaoyazi/GOT optical upper limit
  96. GRB 230427A: OHP/T193 spectroscopy observations of WISEA J101316.01+481158.7
  97. GRB 230427A: Nanshan/HMT optical upper limit
  98. GRB 230427A: Osservatorio Astronomico Nastro verde upper limit
  99. GRB 230427A: OSIRIS+/GTC observations
  100. Fermi trigger No 704365743: Global MASTER-Net observations report

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