Brooklyn has a new high-tech arena, a new NBA basketball team and a popular three-star Michelin restaurant. Now it has a private equity fund dedicated to investing in the borough’s residential property. Manhattan-based developers East River Partners are raising a $25 million fund to target Brooklyn townhouses and midrise buildings, which it will gut renovate to convert these rental buildings into condos. So far the fund has raised about $10 million from wealthy individuals and acquired three buildings in Park Slope and Carroll Gardens for about $12 million. That includes about $7.8 million in debt. Each property will have five to 10 units with asking prices ranging from $800,000 to $1.8 million for two to three bedrooms. “It’s great time for people to buy in Brooklyn because rents are so strong right now and interest rates are low,” says Jody Kriss, one of East River’s co-founders.