Lynch/Keegan Ancestors

I am looking for information on my ancestor Peter Lynch and his wife Mary Keegan. According to my grandmother, they lived in Carpenterstown in County Westmeath. Using rootsireland.ie, I find that they were married in 1836 in Mount Nugent parish, which is now in County Meath. They had 4 children, Edward born in 1838, Mary born in 1840, Peter born in 1843 and Ellen born in 1845. All 4 children were baptised in Mount Nugent. The father, Peter Lynch, died, possibly in Clenmellon parish in 1847. The child Edward must have died young because the mother and the other 3 children emigrated to Worcester Massachusetts. The mother Mary emigrated before the children. She married a James Hickey who was also from Ireland, but I don't know if they married in Ireland or the US. The children, Mary, Peter and Ellen arrived in April 1852 accompanied by Ellen Keegan age 30. Ellen Keegan was also listed as a sponsor on Mary Lynch's 1840 baptism. Any information on the parents and families of Peter Lynch and Mary Keegan would be gratefully appreciated.