Richard Mather came to America without Hannah in September 1848, so Hannah had presumed died by then. The Hannah (Sharples) that died 1839 was wife of another Richard from Bury. Cant find Hannah on the 1841 census, although Richard is there (60, Ag Lab) at Sharples, so Hannah may have died before 1841. There is a Hannah Mather died Q4/1844, Turton, aged 64 and another died 1848, Little Bolton, aged 68. One of these was at Dawes St, Bolton in 1841 (Not from Lancashire with son Samuel an Iron Moulder)
Lancashire Death indexes for the years: 1844
MATHER Hannah 64 Turton TUR/2/373
MATHER, HANNAH 64
GRO Reference: 1844 D Quarter in BOLTON UNION
Volume 21 Page 133
There are several possible Hannah deaths:
1827 Hannah Mather, Aged 51, Bolton le Moors, buried 25 Nov 1827, wife of William Mather (but I cant find a Willian & Hannah family)
The 3 Feb 1839 burial at St. Johns, Bury is quite close to Harwood where they lived, but Hannah Sharples (1805-1839) wife of another Richard Mather.
Hannah wife of Richard Mather of Pigslee, aged 34 Years
No Hannah death registered, but possibly Anna:
Deaths Mar 1839 (>99%)
MATHER Anna Bury 21 248
This may be Anna from Walmersley, aged 34 - so not her!