Low-income students in California are missing out on millions of dollars of federal aid they're eligible to receive, according to a new research brief.

The state's community college students missed out on nearly $130 million in federal Pell Grant funds in a single semester, according to research from the Wheelhouse Center for Community College Leadership and Research at the University of California, Davis, School of Education.

"Given how many low-income students we serve here, it's critical they get the aid they're entitled to," said Susanna Cooper, managing director of the Wheelhouse Center. "California pays more in [federal taxes] than it gets back in terms of benefits, and here's an instance where benefits are being left on the table and could be coming back to California, but we're not taking advantage of it."

In 2015, more than 471,000 California students received Pell Grants. But the researchers discovered that more than 20 percent of the state's two-year college students who successfully applied for aid, demonstrated their financial eligibility and enrolled in the required number of credits still did not receive federal aid. The researchers took a sample of about 320,000 students who were enrolled in 2014 and found nearly 71,000 of them seemed to be Pell eligible but did not receive the grant.

California's community colleges already boast some of the lowest tuition fees in the country. The state's tuition-waiver program -- the California College Promise Grant, formerly known as the Board of Governors fee waiver program -- covers about 43 percent of community college students' tuition costs.

"When a student gets a BOG waiver, this is tuition-covered aid they qualify for, not realizing the Pell can help pay for rent, transportation, books and food," Cooper said. "We've seen new survey research about how many college students are hungry and this is exactly what Pell is expected to address, but it may be they just don't know it."

There may be several other issues preventing students from accepting federal aid, Cooper said, adding that challenges around the Free Application for Federal Student Aid verification process could be part of the problem.

Previous studies have calculated the amount of aid left on the table by students who could have been eligible but didn't apply. For example, a national study by the Campaign for College Opportunity found that in 2014, nearly 1.5 million high school graduates failed to complete the FAFSA, leaving about $2.7 billion in Pell Grants unused.

But, increasingly, advocates for low-income students are learning about verification melt -- or the idea that students will apply for aid but panic when they receive a notice about the verification process.

"They don't know where to turn or go to for support to fill that form," said Audrey Dow, senior vice president at the Campaign for College Opportunity. "Think about it as getting a notice from the Internal Revenue Service that you're getting audited. The panic sets in and often students stop at that point."

Low-income students are more likely to be subjected to verification. And while the process may seem easy to some, students often worry their financial information will be called into question. Some also are wary about disclosing their family history or immigration status, Dow said.

"It is a national problem," she said. "There have been really good policies under the Obama administration to significantly simplify the FAFSA, and we should be lauding those things."

Dow said financial aid counselors have an opportunity to provide more assistance and to help make the process simpler.

The nationwide problem of students not taking advantage of financial aid could be connected to the student loan debt crisis, said Debbie Cochrane, vice president of the Institute for College Access and Success. But it’s a completion issue in California.

"Very few students in the California college system take out loans," she said. "They're finding other ways to stay engaged, which means they're taking fewer courses and making more time for work. They're prioritizing working over studying."

Studies also have found that the longer it takes a student to complete college, the more opportunities they have to drop out.

"Why would we expect an 18-year-old or a 17-year-old to do their own taxes when adults pay an accountant?" Dow said. "We have to shift our mind-set on how we as college institutions and high schools can better serve our students with providing hands-on support to complete" the FAFSA.

In California, the simplicity of the fee waiver could mean that students are less likely to complete the paperwork needed to receive federal aid, especially once they reach the verification process.

"If you don't need to do that to pay for your tuition, then the urgency of doing all the paperwork is less," said Paco Martorell, an associate professor at UC Davis and one of the brief's coauthors. "There could be institutional factors where the colleges might not have enough student supports needed to get assistance with the paperwork."

While the UC Davis research focused on one semester, Martorell said examining the effects of not receiving Pell money over the course of two, five or six years -- the typical amount of time a student may stay in a community college -- would show a significant loss in aid.

The researchers also found that this problem isn't isolated to any particular student demographics or campus characteristic.

Even after controlling for those factors, Martorell said, the Pell Grant take-up rates varied widely by campus.

"It occurs pretty much everywhere," he said. "We were surprised to see it's not concentrated at schools that are larger or smaller or serve certain populations of students. What we're going to do now is see what institutional practices and policies correlated with this, and we'll expect to see a little bit more of an association with those variables."