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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

16286 results found.

  1. GRB 200325B: Swift-XRT and UVOT observations
  2. GRB 200325B: LCO Optical Detection
  3. GRB 200324A: AROMA-N Optical Observation
  4. GRB 200324A:: TSHAO optical upper limit
  5. GRB 200324A: Swift/UVOT Upper Limits
  6. GRB 200324A: LCO Optical Upper Limit
  7. GRB 200324A: Konkoly Obs. optical upper limit
  8. GRB 200324A: NOT optical upper limit
  9. GRB 200324A: Tautenburg observations
  10. GRB 200324A:MITSuME Akeno optical upper limits
  11. GW170817: Continued X-ray emission detected with Chandra at 940 days post-merger
  12. LIGO/Virgo S200316bj: No Counterparts in DDOTI/OAN Optical Observations
  13. LIGO/Virgo S200213t: Continued Swift UVOT and XRT observations of ZTF20aamvmzj (AT2020cja)
  14. SGR Swift J1818.0-1607: BOOTES-4/MET optical limit
  15. GRB 200306C: ALMA 3mm upper limit
  16. GRB 200306A: Swift/UVOT Upper Limits
  17. GRB 200306A: RATIR Optical Observations
  18. GRB 200306C: VIRT optical upper limits
  19. GRB 200306C: KCT upper limit of the optical afterglow
  20. GRB 200306C: LCO Optical Upper Limits
  21. GRB 200306C: OSN 1.5m afterglow detection
  22. GRB 200306C: GOTO upper limits
  23. LIGO/Virgo S200302c: No notable candidates in GOTO imaging
  24. GRB 200306C: BOOTES-1 detection of the optical afterglow
  25. GRB 200306C: Swift detection of a burst with an optical counterpart
  26. Swift GRB200306.95: Global MASTER-Net OT detection
  27. Swift GRB200306.95: Global MASTER-Net OT detection
  28. GRB 200306A: Potential LCO Optical Afterglow Detection
  29. GRB 200228B: continued optical observations
  30. LIGO/Virgo S200225q: No notable candidates in GOTO imaging
  31. GRB 200303A: NOT optical observations
  32. GRB 200303A: Swift/UVOT Upper Limits
  33. GRB 200303A: FRAM-ORM optical limit
  34. GRB 200303A: GOTO observations upper limit
  35. GRB 200303A: Optical limit from CAHA
  36. GRB 200219C: VLA Detection
  37. LIGO/Virgo S200224ca: No counterpart candidates in TOROS observations
  38. GRB 200228B: Mondy, TSHAO, AbAO and CrAO optical observations, afterglow candidate
  39. GRB 200228B: LCO Optical Upper Limit
  40. GRB 200228B: RATIR Optical Observations
  41. GRB 200228B: Swift/UVOT Upper Limits
  42. GRB 200228B: RATIR Optical Observations
  43. GRB 200227A: RATIR Optical Observations
  44. GRB 200228B: KAIT Optical Upper Limit
  45. LIGO/Virgo S200213t: No significant EM counterparts identified from continued GECKO observation of host galaxy candidates
  46. GRB 200227A: Mondy optical upper limit
  47. GRB 200227A: Swift/UVOT Upper Limits
  48. GRB 200224A: Mondy optical upper limit
  49. GRB 200227A: MITSuME Akeno optical upper limit
  50. LIGO/Virgo S200224ca: DESGW Optical counterpart candidates from DECam
  51. GRB 200224A: Calar Alto 2.2m optical afterglow detection
  52. GRB 200224B: DDOTI/OAN optical observations report
  53. LIGO/Virgo S200224ca: No Counterparts in DDOTI/OAN Optical Observations
  54. LIGO/Virgo S200224ca: Subaru/Hyper Suprime-Cam follow-up observations
  55. LIGO/Virgo S200219ac: No counterpart candidates from Nanshan/NEXT observations
  56. GRB 200224A: RATIR Optical Observations and Confirmation of the Afterglow
  57. GRB 200224A: Swift/UVOT Detection
  58. GRB 200224A: Tautenburg observations
  59. GRB 200224A: BOOTES-1 and 1.5m OSN optical observations
  60. GRB 200219A: UVOT Upper Limits
  61. GRB 200219A: FRAM-Auger optical limit
  62. GRB 200219C: Mondy and TSHAO optical observations
  63. GRB 200219C: Nanshan/NEXT optical upper limit and possible host galaxy from PanSTARRS
  64. GRB 200219C: DDOTI Observations
  65. LIGO/Virgo S200213t: AT2020clw/ZTF20aanaoyz, AT2020crd/ZTF20aanakge and AT2020cly/ZTF20aanakes 10.4m GTC spectroscopy
  66. GRB 200215A: LCO Optical Upper Limits
  67. LIGO/Virgo S200213t: Keck/LRIS spectroscopy of counterpart candidates from the Zwicky Transient Facility
  68. GRB 200216B: second epoch optical upper limit at Mondy observatory
  69. GRB 200216B: Mondy and AbAO optical upper limits
  70. LIGO/Virgo S200213t: No EM counterparts found from continued GECKO observation of host galaxy candidates
  71. GRB 200216B: z-band limit from NOT
  72. GRB 200216B: Swift/UVOT Upper Limits
  73. GRB 200215A: RATIR Optical Observations
  74. GRB 200216B: Nanshan/NEXT early optical upper limit and possible host galaxy
  75. GRB 200216B: GMG upper limit
  76. GRB 200215A: Swift/UVOT Upper Limits
  77. GRB 200215A: Optical observations form Calar Alto 2.2m
  78. GRB 200215A: Nanshan/NEXT optical upper limit
  79. LIGO/Virgo S200213t: MASTER possible Kilonova candidate in PGC315337
  80. LIGO/Virgo S200213t: P200 Spectroscopy of ZTF20aanakcd/AT2020cmr
  81. LIGO/Virgo S200213t: DBSP spectroscopy of AT2020cjb/ZTF20aamvnth, AT2020cja/ZTF20aamvmzj, AT2020cjc/ZTF20aamvoeh
  82. LIGO/Virgo S200114f: Gemini Spectra of AT 2020vu, AT 2020vw, AT 2020vy, and AT 2020vz
  83. LIGO/Virgo S200213t: MASTER OT detection in PGC673735
  84. LIGO/Virgo S200213t: No counterpart candidates from Nanshan-0.6m observations
  85. LIGO/Virgo S200213t: No notable candidates in GOTO imaging
  86. LIGO/Virgo S200213t: No Counterparts from GECKO observation of host galaxy candidates in GW-neutrino detection overlap area
  87. LIGO/Virgo S200213t: More Candidates from the Zwicky Transient Facility
  88. LIGO/Virgo S200213t: AT2020ciz/ZTF20aamvnat, AT2020cjb/ZTF20aamvnth and 2020cjf/ZTF20aamvodd 10.4m GTC spectroscopy
  89. LIGO/Virgo S200213t: No Counterparts in DDOTI/OAN Optical Observations
  90. LIGO/Virgo S200213t: AT2020ciy/ZTF20aamvqxl, AT2020cjg/ZTF20aamvoxx and AT2020cje/ZTF20aamvtip 10.4m GTC spectroscopy
  91. LIGO/Virgo S191213g: AT2019wxt Wendelstein optical observations
  92. GRB 200131A: Tautenburg observations
  93. GRB 200205B: Chilescope optical observations
  94. GRB 200205B: ESO/NTT near-infrared imaging
  95. GRB 200205A = Swift J0840.7-3516: optical photometry in Chilescope observatory
  96. GRB 200205B: VLT/X-shooter redshift
  97. GRB 200205B: LCO Optical Detection
  98. GRB 200205B: Swift detection of a burst with optical counterpart
  99. Swift GRB200205.81: Global MASTER-Net OT detection
  100. GRB 200205A / Swift trigger 954304: VLT optical observations

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