The slowing economy could delay Brooklyn’s Atlantic Yards mega-project by several years, developer Bruce Ratner says. The Miss Brooklyn office tower, originally scheduled to be completed in July 2009, has yet to secure an anchor tenant, and Ratner has resorted to sending a letter written by architect Frank Gehry to CEOs, inviting them to become part of the project’s “centerpiece.” Ratner said he remains confident in the Brooklyn office market, but said the office tower won’t be built until an anchor tenant is found. Ratner also said “the bond market may slow the pace of the residential buildings.” Atlantic Yards has already been delayed by several lawsuits, and two remain on appeal. Some critics worry that more delays will lead Ratner to demand more public subsidies, reduce the amount of affordable housing included or even sell parcels to other developers who could use less expensive designs. Ratner says the 18,000-seat Nets basketball arena will be built on schedule.