The gunman who killed 11 worshipers in a Pittsburgh synagogue will be formally sentenced to death on Thursday morning by the judge who presided over the three-month trial in U.S. district court.

Jurors in the case decided on Wednesday that the gunman, Robert Bowers, should be given the death penalty, and the judge, Robert Colville, is bound by the jury’s decision.

But the hearing could be more than the imposition of the sentence.

Family members of those who were killed will have a chance, “to share the impact of their losses, to describe how the defendant’s crimes have impacted them and their families,” said Eric Olshan, the U.S. attorney for the Western District of Pennsylvania.

Unlike the penalty phase of the trial, when some relatives were called to testify and asked about the magnitude of their losses, Thursday’s hearing will allow them to speak on their own terms.

The judge himself may offer some remarks about the October 2018 mass shooting, considered the deadliest antisemitic attack in the country’s history. It is unclear whether Mr. Bowers, 50, who has said nothing publicly since the morning of the attack, will address the court before he is sentenced.

The judge also has to hand down sentences on the dozens of convictions that did not carry a death sentence. The jury’s recommendation of death concerned the 22 hate crimes and civil rights offenses connected to the killings that Mr. Bowers carried out in the synagogue. But he was convicted on 41 other federal counts, too, including firearms charges .

“Those are counts on which he was found guilty, and therefore he must receive a sentence, and the sentence has to be in accordance with the law,” said David Harris, a professor at the University of Pittsburgh School of Law.

In the unlikely event that Mr. Bowers’s death sentence were overturned, Professor Harris said, he would still be incarcerated on these other convictions. “He didn’t only murder these people, he did other things, too. And so we recognize the whole of the case, even though carrying out the death sentence would take care of any other sentence that he faces.”

What happens beyond this hearing is less clear. Like all people sentenced to death, Mr. Bowers was automatically granted an appeal, and his lawyers have indicated that they intend to pursue it.

He was also charged with 36 counts in state court, including 11 counts of murder. Days after the attack, the district attorney of Allegheny County, which includes Pittsburgh, agreed to pause its prosecution while the federal process unfolded.

In a statement on Wednesday, the district attorney’s office said that because of the “emotional strain” of the federal trial, “it would be inappropriate for us to comment on our charges until we have had a chance to meet with the families.”